diff --git a/qt/python/mantidqt/mantidqt/_common.sip b/qt/python/mantidqt/mantidqt/_common.sip
index 57fb824407ff..bbba2c2c95b0 100644
--- a/qt/python/mantidqt/mantidqt/_common.sip
+++ b/qt/python/mantidqt/mantidqt/_common.sip
@@ -911,10 +911,10 @@ public:
     void setNumberOfDatasets(int n);
     void setCurrentDataset(int i) throw(std::exception);
     int getCurrentDataset() const;
-    void setDatasets(const QStringList &datasetNames);
-    void addDatasets(const QStringList &names);
+    void setDatasets(const std::vector<std::string> &datasetNames);
+    void addDatasets(const std::vector<std::string> &names);
     void removeDatasets(QList<int> indices);
-    QStringList getDatasetNames() const;
+    std::vector<std::string> getDatasetNames() const;
     void setErrorsEnabled(bool enabled);
     void hideGlobalCheckbox();
     void showGlobalCheckbox();
diff --git a/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.cpp b/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.cpp
index 7c9406e2215f..ab4e82b90777 100644
--- a/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.cpp
+++ b/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.cpp
@@ -5,6 +5,7 @@
 //   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
 // SPDX - License - Identifier: GPL - 3.0 +
 #include "Common/InterfaceUtils.h"
+#include "Common/SettingsHelper.h"
 #include "MantidKernel/Logger.h"
 #include "MantidQtWidgets/Common/ParseKeyValueString.h"
 #include <QDomDocument>
@@ -67,6 +68,11 @@ static std::string getInterfaceAttribute(QDomElement const &root, std::string co
   return "";
 }
 
+/// The function to use to check whether input data should be restricted based on its name.
+/// This is defined, rather than calling SettingsHelper::restrictInputDataByName() directly, to make it
+/// possible to override it in tests in order to mock out the SettingsHelper.
+std::function<bool()> restrictInputDataByName = SettingsHelper::restrictInputDataByName;
+
 std::string getInterfaceProperty(std::string const &interfaceName, std::string const &propertyName,
                                  std::string const &attribute) {
   QFile file(":/interface-properties.xml");
@@ -87,52 +93,58 @@ QStringList getCalibrationExtensions(std::string const &interfaceName) {
   return toQStringList(getInterfaceProperty(interfaceName, "EXTENSIONS", "calibration"), ",");
 }
 
-QStringList getSampleFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "sample"), ",");
+QStringList getFBSuffixes(std::string const &interfaceName, std::string const &fileType) {
+  if (!restrictInputDataByName()) {
+    return getExtensions(interfaceName);
+  }
+  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", fileType), ",");
 }
 
-QStringList getSampleWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "sample"), ",");
+QStringList getWSSuffixes(std::string const &interfaceName, std::string const &fileType) {
+  if (!restrictInputDataByName()) {
+    return QStringList{""};
+  }
+  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", fileType), ",");
 }
 
-QStringList getVanadiumFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "vanadium"), ",");
-}
+QStringList getSampleFBSuffixes(std::string const &interfaceName) { return getFBSuffixes(interfaceName, "sample"); }
 
-QStringList getVanadiumWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "vanadium"), ",");
-}
+QStringList getSampleWSSuffixes(std::string const &interfaceName) { return getWSSuffixes(interfaceName, "sample"); }
+
+QStringList getVanadiumFBSuffixes(std::string const &interfaceName) { return getFBSuffixes(interfaceName, "vanadium"); }
+
+QStringList getVanadiumWSSuffixes(std::string const &interfaceName) { return getWSSuffixes(interfaceName, "vanadium"); }
 
 QStringList getResolutionFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "resolution"), ",");
+  return getFBSuffixes(interfaceName, "resolution");
 }
 
 QStringList getResolutionWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "resolution"), ",");
+  return getWSSuffixes(interfaceName, "resolution");
 }
 
 QStringList getCalibrationFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "calibration"), ",");
+  return getFBSuffixes(interfaceName, "calibration");
 }
 
 QStringList getCalibrationWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "calibration"), ",");
+  return getWSSuffixes(interfaceName, "calibration");
 }
 
 QStringList getContainerFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "container"), ",");
+  return getFBSuffixes(interfaceName, "container");
 }
 
 QStringList getContainerWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "container"), ",");
+  return getWSSuffixes(interfaceName, "container");
 }
 
 QStringList getCorrectionsFBSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "FILE-SUFFIXES", "corrections"), ",");
+  return getFBSuffixes(interfaceName, "corrections");
 }
 
 QStringList getCorrectionsWSSuffixes(std::string const &interfaceName) {
-  return toQStringList(getInterfaceProperty(interfaceName, "WORKSPACE-SUFFIXES", "corrections"), ",");
+  return getWSSuffixes(interfaceName, "corrections");
 }
 
 QPair<double, double> convertTupleToQPair(std::tuple<double, double> const &doubleTuple) {
diff --git a/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.h b/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.h
index af647d54ca23..306e4b38c75d 100644
--- a/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.h
+++ b/qt/scientific_interfaces/Inelastic/Common/InterfaceUtils.h
@@ -14,6 +14,11 @@ namespace MantidQt {
 namespace CustomInterfaces {
 namespace InterfaceUtils {
 
+/// The function to use to check whether input data should be restricted based on its name.
+/// This is defined, rather than calling SettingsHelper::restrictInputDataByName() directly, to make it
+/// possible to override it in tests in order to mock out the SettingsHelper.
+MANTIDQT_INELASTIC_DLL extern std::function<bool()> restrictInputDataByName;
+
 MANTIDQT_INELASTIC_DLL std::string getInterfaceProperty(std::string const &interfaceName,
                                                         std::string const &propertyName, std::string const &attribute);
 
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.cpp
index 9ad77b8c164a..a395e24bed6f 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.cpp
@@ -5,7 +5,9 @@
 //   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
 // SPDX - License - Identifier: GPL - 3.0 +
 #include "ConvFitDataView.h"
+#include "Common/InterfaceUtils.h"
 #include "ConvFitAddWorkspaceDialog.h"
+#include "FitDataPresenter.h"
 
 #include <QComboBox>
 #include <QHeaderView>
@@ -38,11 +40,12 @@ void ConvFitDataView::showAddWorkspaceDialog() {
   connect(dialog, SIGNAL(addData(MantidWidgets::IAddWorkspaceDialog *)), this,
           SLOT(notifyAddData(MantidWidgets::IAddWorkspaceDialog *)));
 
+  auto tabName = m_presenter->tabName();
   dialog->setAttribute(Qt::WA_DeleteOnClose);
-  dialog->setWSSuffices(m_wsSampleSuffixes);
-  dialog->setFBSuffices(m_fbSampleSuffixes);
-  dialog->setResolutionWSSuffices(m_wsResolutionSuffixes);
-  dialog->setResolutionFBSuffices(m_fbResolutionSuffixes);
+  dialog->setWSSuffices(InterfaceUtils::getSampleWSSuffixes(tabName));
+  dialog->setFBSuffices(InterfaceUtils::getSampleFBSuffixes(tabName));
+  dialog->setResolutionWSSuffices(InterfaceUtils::getResolutionWSSuffixes(tabName));
+  dialog->setResolutionFBSuffices(InterfaceUtils::getResolutionFBSuffixes(tabName));
   dialog->updateSelectedSpectra();
   dialog->show();
 }
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.h b/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.h
index 98788721e201..a57dc98483c9 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/ConvFitDataView.h
@@ -22,11 +22,11 @@ Presenter for a table of convolution fitting data.
 class MANTIDQT_INELASTIC_DLL ConvFitDataView : public FitDataView {
   Q_OBJECT
 public:
-  ConvFitDataView(QWidget *parent = nullptr);
+  ConvFitDataView(QWidget *parent);
   void addTableEntry(size_t row, FitDataRow newRow) override;
 
 protected:
-  ConvFitDataView(const QStringList &headers, QWidget *parent = nullptr);
+  ConvFitDataView(const QStringList &headers, QWidget *parent);
 
 protected slots:
   void showAddWorkspaceDialog() override;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.cpp
index 953d4c05fe09..cff40b236884 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.cpp
@@ -61,6 +61,11 @@ FunctionModelSpectra FitDataModel::getSpectra(WorkspaceID workspaceID) const {
   return FunctionModelSpectra("");
 }
 
+FunctionModelDataset FitDataModel::getDataset(WorkspaceID workspaceID) const {
+  auto const name = getWorkspace(workspaceID)->getName();
+  return FunctionModelDataset(name, getSpectra(workspaceID));
+}
+
 std::string FitDataModel::createDisplayName(WorkspaceID workspaceID) const {
   if (getNumberOfWorkspaces() > workspaceID)
     return getFitDataName(getWorkspaceNames()[workspaceID.value], getSpectra(workspaceID));
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.h
index 4c715a392dff..fd8a92e664b7 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataModel.h
@@ -11,6 +11,7 @@
 #include "IFitDataModel.h"
 
 #include "MantidAPI/MatrixWorkspace.h"
+#include "MantidQtWidgets/Common/FunctionModelDataset.h"
 #include "MantidQtWidgets/Common/FunctionModelSpectra.h"
 #include "MantidQtWidgets/Common/IndexTypes.h"
 
@@ -43,6 +44,7 @@ class MANTIDQT_INELASTIC_DLL FitDataModel : public IFitDataModel {
   void setSpectra(FunctionModelSpectra &&spectra, WorkspaceID workspaceID) override;
   void setSpectra(const FunctionModelSpectra &spectra, WorkspaceID workspaceID) override;
   FunctionModelSpectra getSpectra(WorkspaceID workspaceID) const override;
+  FunctionModelDataset getDataset(WorkspaceID workspaceID) const override;
   size_t getSpectrum(FitDomainIndex index) const override;
   size_t getNumberOfSpectra(WorkspaceID workspaceID) const override;
 
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.cpp
index f684632649a1..7bd5655e1683 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.cpp
@@ -26,6 +26,8 @@ std::vector<FitData> *FitDataPresenter::getFittingData() { return m_model->getFi
 
 IFitDataView const *FitDataPresenter::getView() const { return m_view; }
 
+std::string FitDataPresenter::tabName() const { return m_tab->tabName(); }
+
 bool FitDataPresenter::addWorkspaceFromDialog(MantidWidgets::IAddWorkspaceDialog const *dialog) {
   if (const auto indirectDialog = dynamic_cast<MantidWidgets::AddWorkspaceDialog const *>(dialog)) {
     addWorkspace(indirectDialog->workspaceName(), indirectDialog->workspaceIndices());
@@ -45,18 +47,6 @@ void FitDataPresenter::setResolution(const std::string &name) {
   }
 }
 
-void FitDataPresenter::setSampleWSSuffices(const QStringList &suffixes) { m_view->setSampleWSSuffices(suffixes); }
-
-void FitDataPresenter::setSampleFBSuffices(const QStringList &suffixes) { m_view->setSampleFBSuffices(suffixes); }
-
-void FitDataPresenter::setResolutionWSSuffices(const QStringList &suffixes) {
-  m_view->setResolutionWSSuffices(suffixes);
-}
-
-void FitDataPresenter::setResolutionFBSuffices(const QStringList &suffixes) {
-  m_view->setResolutionFBSuffices(suffixes);
-}
-
 void FitDataPresenter::setStartX(double startX, WorkspaceID workspaceID) {
   if (m_model->getNumberOfWorkspaces() > workspaceID) {
     m_model->setStartX(startX, workspaceID);
@@ -85,7 +75,7 @@ std::vector<std::pair<std::string, size_t>> FitDataPresenter::getResolutionsForF
   return m_model->getResolutionsForFit();
 }
 
-UserInputValidator &FitDataPresenter::validate(UserInputValidator &validator) { return m_view->validate(validator); }
+void FitDataPresenter::validate(UserInputValidator &validator) { m_view->validate(validator); }
 
 void FitDataPresenter::handleAddData(MantidWidgets::IAddWorkspaceDialog const *dialog) {
   try {
@@ -110,8 +100,14 @@ WorkspaceID FitDataPresenter::getNumberOfWorkspaces() const { return m_model->ge
 
 size_t FitDataPresenter::getNumberOfDomains() const { return m_model->getNumberOfDomains(); }
 
-FunctionModelSpectra FitDataPresenter::getSpectra(WorkspaceID workspaceID) const {
-  return m_model->getSpectra(workspaceID);
+QList<FunctionModelDataset> FitDataPresenter::getDatasets() const {
+  QList<FunctionModelDataset> datasets;
+
+  for (auto i = 0u; i < m_model->getNumberOfWorkspaces().value; ++i) {
+    WorkspaceID workspaceID{i};
+    datasets.append(m_model->getDataset(workspaceID));
+  }
+  return datasets;
 }
 
 DataForParameterEstimationCollection
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.h
index 03b1fc41f817..d91e20bc218f 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataPresenter.h
@@ -24,6 +24,8 @@ class IFitTab;
 
 class MANTIDQT_INELASTIC_DLL IFitDataPresenter {
 public:
+  virtual std::string tabName() const = 0;
+
   virtual void handleAddData(MantidWidgets::IAddWorkspaceDialog const *dialog) = 0;
   virtual void handleRemoveClicked() = 0;
   virtual void handleUnifyClicked() = 0;
@@ -38,10 +40,6 @@ class MANTIDQT_INELASTIC_DLL FitDataPresenter : public IFitDataPresenter, public
   virtual bool addWorkspaceFromDialog(MantidWidgets::IAddWorkspaceDialog const *dialog);
   void addWorkspace(const std::string &workspaceName, const FunctionModelSpectra &workspaceIndices);
   void setResolution(const std::string &name);
-  void setSampleWSSuffices(const QStringList &suffices);
-  void setSampleFBSuffices(const QStringList &suffices);
-  void setResolutionWSSuffices(const QStringList &suffices);
-  void setResolutionFBSuffices(const QStringList &suffices);
   void setStartX(double startX, WorkspaceID workspaceID);
   void setStartX(double startX, WorkspaceID workspaceID, WorkspaceIndex spectrum);
   void setEndX(double startX, WorkspaceID workspaceID);
@@ -52,11 +50,11 @@ class MANTIDQT_INELASTIC_DLL FitDataPresenter : public IFitDataPresenter, public
   void updateTableFromModel();
   WorkspaceID getNumberOfWorkspaces() const;
   size_t getNumberOfDomains() const;
-  FunctionModelSpectra getSpectra(WorkspaceID workspaceID) const;
+  QList<FunctionModelDataset> getDatasets() const;
   DataForParameterEstimationCollection getDataForParameterEstimation(const EstimationDataSelector &selector) const;
   std::vector<double> getQValuesForData() const;
   std::vector<std::string> createDisplayNames() const;
-  UserInputValidator &validate(UserInputValidator &validator);
+  void validate(UserInputValidator &validator);
 
   virtual void addWorkspace(const std::string &workspaceName, const std::string &paramType, const int &spectrum_index) {
     UNUSED_ARG(workspaceName);
@@ -77,6 +75,8 @@ class MANTIDQT_INELASTIC_DLL FitDataPresenter : public IFitDataPresenter, public
 
   virtual void subscribeFitPropertyBrowser(IInelasticFitPropertyBrowser *browser) { UNUSED_ARG(browser); };
 
+  std::string tabName() const override;
+
   void handleAddData(MantidWidgets::IAddWorkspaceDialog const *dialog) override;
   void handleRemoveClicked() override;
   void handleUnifyClicked() override;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.cpp
index b4ae8bda980c..564f7a0ba0cc 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.cpp
@@ -68,10 +68,9 @@ void FitDataView::setHorizontalHeaders(const QStringList &headers) {
   m_uiForm->tbFitData->verticalHeader()->setVisible(false);
 }
 
-UserInputValidator &FitDataView::validate(UserInputValidator &validator) {
+void FitDataView::validate(UserInputValidator &validator) {
   if (m_uiForm->tbFitData->rowCount() == 0)
     validator.addErrorMessage("No input data has been provided.");
-  return validator;
 }
 
 void FitDataView::displayWarning(const std::string &warning) {
@@ -131,22 +130,15 @@ QModelIndexList FitDataView::getSelectedIndexes() const {
   return m_uiForm->tbFitData->selectionModel()->selectedIndexes();
 }
 
-void FitDataView::setSampleWSSuffices(const QStringList &suffixes) { m_wsSampleSuffixes = suffixes; }
-
-void FitDataView::setSampleFBSuffices(const QStringList &suffixes) { m_fbSampleSuffixes = suffixes; }
-
-void FitDataView::setResolutionWSSuffices(const QStringList &suffixes) { m_wsResolutionSuffixes = suffixes; }
-
-void FitDataView::setResolutionFBSuffices(const QStringList &suffixes) { m_fbResolutionSuffixes = suffixes; }
-
 void FitDataView::showAddWorkspaceDialog() {
   auto dialog = new MantidWidgets::AddWorkspaceDialog(parentWidget());
   connect(dialog, SIGNAL(addData(MantidWidgets::IAddWorkspaceDialog *)), this,
           SLOT(notifyAddData(MantidWidgets::IAddWorkspaceDialog *)));
 
+  auto tabName = m_presenter->tabName();
   dialog->setAttribute(Qt::WA_DeleteOnClose);
-  dialog->setWSSuffices(m_wsSampleSuffixes);
-  dialog->setFBSuffices(m_fbSampleSuffixes);
+  dialog->setWSSuffices(InterfaceUtils::getSampleWSSuffixes(tabName));
+  dialog->setFBSuffices(InterfaceUtils::getSampleFBSuffixes(tabName));
   dialog->updateSelectedSpectra();
   dialog->show();
 }
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.h
index c098960abc55..cb4030fc0b93 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitDataView.h
@@ -36,7 +36,7 @@ class MANTIDQT_INELASTIC_DLL FitDataView : public QTabWidget, public IFitDataVie
   QTableWidget *getDataTable() const override;
   bool isTableEmpty() const override;
 
-  UserInputValidator &validate(UserInputValidator &validator) override;
+  void validate(UserInputValidator &validator) override;
   virtual void addTableEntry(size_t row, FitDataRow newRow) override;
   virtual void updateNumCellEntry(double numEntry, size_t row, size_t column) override;
   int getColumnIndexFromName(std::string const &ColName) override;
@@ -45,11 +45,6 @@ class MANTIDQT_INELASTIC_DLL FitDataView : public QTabWidget, public IFitDataVie
   QModelIndexList getSelectedIndexes() const override;
   bool dataColumnContainsText(std::string const &columnText) const override;
 
-  void setSampleWSSuffices(const QStringList &suffices) override;
-  void setSampleFBSuffices(const QStringList &suffices) override;
-  void setResolutionWSSuffices(const QStringList &suffices) override;
-  void setResolutionFBSuffices(const QStringList &suffices) override;
-
   void displayWarning(const std::string &warning) override;
 
 protected slots:
@@ -61,11 +56,6 @@ protected slots:
   std::unique_ptr<Ui::FitDataView> m_uiForm;
   void setCell(std::unique_ptr<QTableWidgetItem> cell, size_t row, size_t column);
 
-  QStringList m_wsSampleSuffixes;
-  QStringList m_fbSampleSuffixes;
-  QStringList m_wsResolutionSuffixes;
-  QStringList m_fbResolutionSuffixes;
-
   IFitDataPresenter *m_presenter;
 
 protected slots:
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.cpp
index caa1d8ce6ce4..38031313495a 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.cpp
@@ -7,75 +7,31 @@
 #include "FitTab.h"
 #include "Common/InterfaceUtils.h"
 #include "Common/SettingsHelper.h"
-#include "MantidQtWidgets/Common/WorkspaceUtils.h"
-
 #include "FitPlotView.h"
-#include "FitTabConstants.h"
 
-#include "MantidAPI/FunctionFactory.h"
 #include "MantidAPI/MultiDomainFunction.h"
-#include "MantidAPI/TextAxis.h"
-#include "MantidAPI/WorkspaceFactory.h"
-
-#include "MantidQtWidgets/Common/FittingMode.h"
-#include "MantidQtWidgets/Common/PropertyHandler.h"
+#include "MantidQtWidgets/Common/WorkspaceUtils.h"
 
-#include <QSignalBlocker>
 #include <QString>
-#include <QtCore>
-
-#include <algorithm>
-#include <utility>
 
 using namespace Mantid::API;
-using namespace MantidQt::MantidWidgets;
-
-namespace {
-/// Logger
-Mantid::Kernel::Logger g_log("QENS Fitting");
-} // namespace
 
 namespace MantidQt {
 namespace CustomInterfaces {
 namespace Inelastic {
 
-/**
- * @param functionName  The name of the function.
- * @param compositeFunction  The function to search within.
- * @return              The number of custom functions, with the specified name,
- *                      included in the selected model.
- */
-size_t FitTab::getNumberOfSpecificFunctionContained(const std::string &functionName,
-                                                    const IFunction *compositeFunction) {
-  // Whilst this could be a free method it would require its own
-  // dll_export in the header, so it's easier to make it static
-  assert(compositeFunction);
-
-  if (compositeFunction->nFunctions() == 0) {
-    return compositeFunction->name() == functionName ? 1 : 0;
-  } else {
-    size_t count{0};
-    for (size_t i{0}; i < compositeFunction->nFunctions(); i++) {
-      count += getNumberOfSpecificFunctionContained(functionName, compositeFunction->getFunction(i).get());
-    }
-    return count;
-  }
-}
-
-FitTab::FitTab(std::string const &tabName, bool const hasResolution, QWidget *parent)
-    : IndirectTab(parent), m_uiForm(new Ui::FitTab), m_tabName(tabName), m_hasResolution(hasResolution) {
+FitTab::FitTab(QWidget *parent, std::string const &tabName)
+    : IndirectTab(parent), m_uiForm(new Ui::FitTab), m_dataPresenter(), m_fittingModel(), m_plotPresenter(),
+      m_outOptionsPresenter(), m_fitPropertyBrowser(), m_fittingAlgorithm() {
   m_uiForm->setupUi(parent);
+  parent->setWindowTitle(QString::fromStdString(tabName));
 }
 
 void FitTab::setup() {
   connect(m_uiForm->pbRun, SIGNAL(clicked()), this, SLOT(runTab()));
   updateResultOptions();
 
-  connectFitPropertyBrowser();
-}
-
-void FitTab::connectFitPropertyBrowser() {
-  connect(m_fitPropertyBrowser, SIGNAL(functionChanged()), this, SLOT(respondToFunctionChanged()));
+  connect(m_fitPropertyBrowser, SIGNAL(functionChanged()), this, SLOT(handleFunctionChanged()));
 }
 
 void FitTab::subscribeFitBrowserToDataPresenter() {
@@ -100,89 +56,21 @@ void FitTab::setupPlotView(std::optional<std::pair<double, double>> const &xPlot
   m_plotPresenter->updatePlots();
 }
 
-void FitTab::setRunIsRunning(bool running) { m_uiForm->pbRun->setText(running ? "Running..." : "Run"); }
-
-void FitTab::setRunEnabled(bool enable) { m_uiForm->pbRun->setEnabled(enable); }
-
-void FitTab::setFileExtensionsByName(bool filter) {
-  auto const tab = getTabName();
-  setSampleSuffixes(tab, filter);
-  if (hasResolution())
-    setResolutionSuffixes(tab, filter);
-}
-
-void FitTab::setSampleSuffixes(std::string const &tab, bool filter) {
-  QStringList const noSuffixes{""};
-  setSampleWSSuffixes(filter ? InterfaceUtils::getSampleWSSuffixes(tab) : noSuffixes);
-  setSampleFBSuffixes(filter ? InterfaceUtils::getSampleFBSuffixes(tab) : InterfaceUtils::getExtensions(tab));
-}
-
-void FitTab::setResolutionSuffixes(std::string const &tab, bool filter) {
-  QStringList const noSuffixes{""};
-  setResolutionWSSuffixes(filter ? InterfaceUtils::getResolutionWSSuffixes(tab) : noSuffixes);
-  setResolutionFBSuffixes(filter ? InterfaceUtils::getResolutionFBSuffixes(tab) : InterfaceUtils::getExtensions(tab));
-}
-
-void FitTab::setSampleWSSuffixes(const QStringList &suffices) { m_dataPresenter->setSampleWSSuffices(suffices); }
-
-void FitTab::setSampleFBSuffixes(const QStringList &suffices) { m_dataPresenter->setSampleFBSuffices(suffices); }
-
-void FitTab::setResolutionWSSuffixes(const QStringList &suffices) {
-  m_dataPresenter->setResolutionWSSuffices(suffices);
-}
-
-void FitTab::setResolutionFBSuffixes(const QStringList &suffices) {
-  m_dataPresenter->setResolutionFBSuffices(suffices);
-}
-
-WorkspaceID FitTab::getSelectedDataIndex() const { return m_plotPresenter->getActiveWorkspaceID(); }
-
-WorkspaceIndex FitTab::getSelectedSpectrum() const { return m_plotPresenter->getActiveWorkspaceIndex(); }
-
-bool FitTab::isRangeCurrentlySelected(WorkspaceID workspaceID, WorkspaceIndex spectrum) const {
-  return m_plotPresenter->isCurrentlySelected(workspaceID, spectrum);
-}
-
-FittingModel *FitTab::getFittingModel() const { return m_fittingModel.get(); }
-
-/**
- * @param functionName  The name of the function.
- * @return              The number of custom functions, with the specified name,
- *                      included in the selected model.
- */
-size_t FitTab::getNumberOfCustomFunctions(const std::string &functionName) const {
-  auto fittingFunction = m_fittingModel->getFitFunction();
-  if (fittingFunction && fittingFunction->nFunctions() > 0)
-    return getNumberOfSpecificFunctionContained(functionName, fittingFunction->getFunction(0).get());
-  else
-    return 0;
-}
-
 void FitTab::setModelFitFunction() {
   auto func = m_fitPropertyBrowser->getFitFunction();
   m_plotPresenter->setFitFunction(func);
   m_fittingModel->setFitFunction(func);
 }
 
-void FitTab::setModelStartX(double startX) {
-  const auto dataIndex = getSelectedDataIndex();
-  m_dataPresenter->setStartX(startX, dataIndex, getSelectedSpectrum());
-}
-
-void FitTab::setModelEndX(double endX) {
-  const auto dataIndex = getSelectedDataIndex();
-  m_dataPresenter->setStartX(endX, dataIndex, getSelectedSpectrum());
-}
-
 void FitTab::handleTableStartXChanged(double startX, WorkspaceID workspaceID, WorkspaceIndex spectrum) {
-  if (isRangeCurrentlySelected(workspaceID, spectrum)) {
+  if (m_plotPresenter->isCurrentlySelected(workspaceID, spectrum)) {
     m_plotPresenter->setStartX(startX);
     m_plotPresenter->updateGuess();
   }
 }
 
 void FitTab::handleTableEndXChanged(double endX, WorkspaceID workspaceID, WorkspaceIndex spectrum) {
-  if (isRangeCurrentlySelected(workspaceID, spectrum)) {
+  if (m_plotPresenter->isCurrentlySelected(workspaceID, spectrum)) {
     m_plotPresenter->setEndX(endX);
     m_plotPresenter->updateGuess();
   }
@@ -204,18 +92,6 @@ void FitTab::handleEndXChanged(double endX) {
   m_dataPresenter->updateTableFromModel();
 }
 
-/**
- * Sets whether fit members should be convolved with the resolution after a fit.
- *
- * @param convolveMembers If true, members are to be convolved.
- */
-void FitTab::setConvolveMembers(bool convolveMembers) {
-  m_fitPropertyBrowser->setConvolveMembers(convolveMembers);
-  // if convolve members is on, output members should also be on
-  if (convolveMembers)
-    m_fitPropertyBrowser->setOutputCompositeMembers(true);
-}
-
 void FitTab::updateFitOutput(bool error) {
   disconnect(m_batchAlgoRunner, SIGNAL(batchComplete(bool)), this, SLOT(updateFitOutput(bool)));
 
@@ -231,10 +107,12 @@ void FitTab::updateSingleFitOutput(bool error) {
   disconnect(m_batchAlgoRunner, SIGNAL(batchComplete(bool)), this, SLOT(updateSingleFitOutput(bool)));
 
   if (error) {
-    m_fittingModel->cleanFailedSingleRun(m_fittingAlgorithm, m_activeWorkspaceID);
+    m_fittingModel->cleanFailedSingleRun(m_fittingAlgorithm, m_plotPresenter->getActiveWorkspaceID());
     m_fittingAlgorithm.reset();
-  } else
-    m_fittingModel->addSingleFitOutput(m_fittingAlgorithm, m_activeWorkspaceID, m_activeSpectrumIndex);
+  } else {
+    m_fittingModel->addSingleFitOutput(m_fittingAlgorithm, m_plotPresenter->getActiveWorkspaceID(),
+                                       m_plotPresenter->getActiveWorkspaceIndex());
+  }
 }
 
 /**
@@ -242,7 +120,6 @@ void FitTab::updateSingleFitOutput(bool error) {
  * and completed within this interface.
  */
 void FitTab::fitAlgorithmComplete(bool error) {
-  setRunIsRunning(false);
   m_plotPresenter->setFitSingleSpectrumIsFitting(false);
   enableFitButtons(true);
   enableOutputOptions(!error);
@@ -256,30 +133,8 @@ void FitTab::fitAlgorithmComplete(bool error) {
   disconnect(m_batchAlgoRunner, SIGNAL(batchComplete(bool)), this, SLOT(fitAlgorithmComplete(bool)));
 }
 
-/**
- * Updates the parameter values and errors in the fit property browser.
- */
-void FitTab::updateParameterValues() {
-  updateParameterValues(m_fittingModel->getParameterValues(getSelectedDataIndex(), getSelectedSpectrum()));
-}
-
-/**
- * Updates the parameter values and errors in the fit property browser.
- *
- * @param parameters  The parameter values to update the browser with.
- */
-void FitTab::updateParameterValues(const std::unordered_map<std::string, ParameterValue> &params) {
-  try {
-    updateFitBrowserParameterValues(params);
-  } catch (const std::out_of_range &) {
-    g_log.warning("Warning issue updating parameter values in fit property browser");
-  } catch (const std::invalid_argument &) {
-    g_log.warning("Warning issue updating parameter values in fit property browser");
-  }
-}
-
 void FitTab::updateFitBrowserParameterValues(const std::unordered_map<std::string, ParameterValue> &params) {
-  IFunction_sptr fun = m_fittingModel->getFitFunction();
+  auto fun = m_fittingModel->getFitFunction();
   if (fun) {
     for (auto const &pair : params) {
       fun->setParameter(pair.first, pair.second.value);
@@ -293,35 +148,28 @@ void FitTab::updateFitBrowserParameterValues(const std::unordered_map<std::strin
 }
 
 void FitTab::updateFitBrowserParameterValuesFromAlg() {
-  try {
-    updateFitBrowserParameterValues();
-    if (m_fittingAlgorithm) {
-      QSignalBlocker blocker(m_fitPropertyBrowser);
-      if (m_fittingModel->getFittingMode() == FittingMode::SEQUENTIAL) {
-        auto const paramWsName = m_fittingAlgorithm->getPropertyValue("OutputParameterWorkspace");
-        auto paramWs = AnalysisDataService::Instance().retrieveWS<ITableWorkspace>(paramWsName);
-        auto rowCount = static_cast<int>(paramWs->rowCount());
-        if (rowCount == static_cast<int>(m_dataPresenter->getNumberOfDomains()))
-          m_fitPropertyBrowser->updateMultiDatasetParameters(*paramWs);
-      } else {
-        IFunction_sptr fun = m_fittingAlgorithm->getProperty("Function");
-        if (fun->getNumberDomains() > 1)
-          m_fitPropertyBrowser->updateMultiDatasetParameters(*fun);
-        else
-          m_fitPropertyBrowser->updateParameters(*fun);
-      }
+  updateFitBrowserParameterValues();
+  if (m_fittingAlgorithm) {
+    QSignalBlocker blocker(m_fitPropertyBrowser);
+    if (m_fittingModel->getFittingMode() == FittingMode::SEQUENTIAL) {
+      auto const paramWsName = m_fittingAlgorithm->getPropertyValue("OutputParameterWorkspace");
+      auto paramWs = AnalysisDataService::Instance().retrieveWS<ITableWorkspace>(paramWsName);
+      auto rowCount = static_cast<int>(paramWs->rowCount());
+      if (rowCount == static_cast<int>(m_dataPresenter->getNumberOfDomains()))
+        m_fitPropertyBrowser->updateMultiDatasetParameters(*paramWs);
+    } else {
+      IFunction_sptr fun = m_fittingAlgorithm->getProperty("Function");
+      if (fun->getNumberDomains() > 1)
+        m_fitPropertyBrowser->updateMultiDatasetParameters(*fun);
+      else
+        m_fitPropertyBrowser->updateParameters(*fun);
     }
-  } catch (const std::out_of_range &) {
-    g_log.warning("Warning issue updating parameter values in fit property browser");
-  } catch (const std::invalid_argument &) {
-    g_log.warning("Warning issue updating parameter values in fit property browser");
   }
 }
 /**
  * Updates the fit output status
  */
 void FitTab::updateFitStatus() {
-
   if (m_fittingModel->getFittingMode() == FittingMode::SIMULTANEOUS) {
     std::string fit_status = m_fittingAlgorithm->getProperty("OutputStatus");
     double chi2 = m_fittingAlgorithm->getProperty("OutputChiSquared");
@@ -339,94 +187,39 @@ void FitTab::updateFitStatus() {
  */
 void FitTab::handlePlotSelectedSpectra() {
   enableFitButtons(false);
-  plotSelectedSpectra(m_outOptionsPresenter->getSpectraToPlot());
+  for (auto const &spectrum : m_outOptionsPresenter->getSpectraToPlot())
+    m_plotter->plotSpectra(spectrum.first, std::to_string(spectrum.second), SettingsHelper::externalPlotErrorBars());
+  m_outOptionsPresenter->clearSpectraToPlot();
   enableFitButtons(true);
   m_outOptionsPresenter->setPlotting(false);
 }
 
-/**
- * Plots the spectra corresponding to the selected parameters
- * @param spectra :: a vector of spectra to plot from a group workspace
- */
-void FitTab::plotSelectedSpectra(std::vector<SpectrumToPlot> const &spectra) {
-  for (auto const &spectrum : spectra)
-    plotSpectrum(spectrum.first, spectrum.second);
-  m_outOptionsPresenter->clearSpectraToPlot();
-}
-
-/**
- * Plots a spectrum with the specified index in a workspace
- * @workspaceName :: the workspace containing the spectrum to plot
- * @index :: the index in the workspace
- * @errorBars :: true if you want error bars to be plotted
- */
-void FitTab::plotSpectrum(std::string const &workspaceName, std::size_t const &index) {
-  m_plotter->plotSpectra(workspaceName, std::to_string(index), SettingsHelper::externalPlotErrorBars());
-}
-
-/**
- * Gets the name used for the base of the result workspaces
- */
-std::string FitTab::getOutputBasename() const { return m_fittingModel->getOutputBasename(); }
-
-/**
- * Gets the Result workspace from a fit
- */
-WorkspaceGroup_sptr FitTab::getResultWorkspace() const { return m_fittingModel->getResultWorkspace(); }
-
-/**
- * Gets the names of the Fit Parameters
- */
-std::vector<std::string> FitTab::getFitParameterNames() const { return m_fittingModel->getFitParameterNames(); }
-
-/**
- * Executes the single fit algorithm defined in this indirect fit analysis tab.
- */
-void FitTab::singleFit() { handleSingleFitClicked(getSelectedDataIndex(), getSelectedSpectrum()); }
-
 void FitTab::handleSingleFitClicked(WorkspaceID workspaceID, WorkspaceIndex spectrum) {
   if (validate()) {
-    m_activeSpectrumIndex = spectrum;
     m_plotPresenter->setFitSingleSpectrumIsFitting(true);
     enableFitButtons(false);
     enableOutputOptions(false);
     m_fittingModel->setFittingMode(FittingMode::SIMULTANEOUS);
-    m_activeWorkspaceID = workspaceID;
     runSingleFit(m_fittingModel->getSingleFit(workspaceID, spectrum));
   }
 }
 
-/**
- * Executes the sequential fit algorithm defined in this indirect fit analysis
- * tab.
- */
-void FitTab::executeFit() {
-  if (validate()) {
-    setRunIsRunning(true);
-    enableFitButtons(false);
-    enableOutputOptions(false);
-    runFitAlgorithm(m_fittingModel->getFittingAlgorithm(m_fittingModel->getFittingMode()));
-  }
-}
-
 bool FitTab::validate() {
   UserInputValidator validator;
   m_dataPresenter->validate(validator);
+  m_fittingModel->validate(validator);
 
-  const auto invalidFunction = m_fittingModel->isInvalidFunction();
-  if (invalidFunction)
-    validator.addErrorMessage(QString::fromStdString(*invalidFunction));
-
-  const auto error = validator.generateErrorMessage();
-  emit showMessageBox(error);
-  return error.isEmpty();
+  const auto error = validator.generateErrorMessage().toStdString();
+  if (!error.empty()) {
+    displayWarning(error);
+  }
+  return error.empty();
 }
 
 /**
  * Called when the 'Run' button is called in the IndirectTab.
  */
 void FitTab::run() {
-  setRunIsRunning(true);
   enableFitButtons(false);
   enableOutputOptions(false);
   m_fittingModel->setFittingMode(m_fitPropertyBrowser->getFittingMode());
@@ -439,7 +232,8 @@ void FitTab::run() {
  * @param enable :: true to enable buttons
  */
 void FitTab::enableFitButtons(bool enable) {
-  setRunEnabled(enable);
+  m_uiForm->pbRun->setText(enable ? "Run" : "Running...");
+  m_uiForm->pbRun->setEnabled(enable);
   m_plotPresenter->setFitSingleSpectrumEnabled(enable);
   m_fitPropertyBrowser->setFitEnabled(enable);
 }
@@ -451,8 +245,8 @@ void FitTab::enableFitButtons(bool enable) {
  */
 void FitTab::enableOutputOptions(bool enable) {
   if (enable) {
-    m_outOptionsPresenter->setResultWorkspace(getResultWorkspace());
-    setPDFWorkspace(getOutputBasename() + "_PDFs");
+    m_outOptionsPresenter->setResultWorkspace(m_fittingModel->getResultWorkspace());
+    setPDFWorkspace(m_fittingModel->getOutputBasename() + "_PDFs");
     m_outOptionsPresenter->setPlotTypes("Result Group");
   } else
     m_outOptionsPresenter->setMultiWorkspaceOptionsVisible(enable);
@@ -482,40 +276,14 @@ void FitTab::setPDFWorkspace(std::string const &workspaceName) {
 void FitTab::updateParameterEstimationData() {
   m_fitPropertyBrowser->updateParameterEstimationData(
       m_dataPresenter->getDataForParameterEstimation(m_fitPropertyBrowser->getEstimationDataSelector()));
-  const bool isFit = m_fittingModel->isPreviouslyFit(getSelectedDataIndex(), getSelectedSpectrum());
+  const bool isFit = m_fittingModel->isPreviouslyFit(m_plotPresenter->getActiveWorkspaceID(),
+                                                     m_plotPresenter->getActiveWorkspaceIndex());
   // If we haven't fit the data yet we may update the guess
   if (!isFit) {
     m_fitPropertyBrowser->estimateFunctionParameters();
   }
 }
 
-/**
- * Sets the visiblity of the output options Edit Result button
- * @param visible :: true to make the edit result button visible
- */
-void FitTab::setEditResultVisible(bool visible) { m_outOptionsPresenter->setEditResultVisible(visible); }
-
-void FitTab::setAlgorithmProperties(const IAlgorithm_sptr &fitAlgorithm) const {
-  fitAlgorithm->setProperty("Minimizer", m_fitPropertyBrowser->minimizer(true));
-  fitAlgorithm->setProperty("MaxIterations", m_fitPropertyBrowser->maxIterations());
-  fitAlgorithm->setProperty("PeakRadius", m_fitPropertyBrowser->getPeakRadius());
-  fitAlgorithm->setProperty("CostFunction", m_fitPropertyBrowser->costFunction());
-  fitAlgorithm->setProperty("IgnoreInvalidData", m_fitPropertyBrowser->ignoreInvalidData());
-  fitAlgorithm->setProperty("EvaluationType", m_fitPropertyBrowser->fitEvaluationType());
-  fitAlgorithm->setProperty("PeakRadius", m_fitPropertyBrowser->getPeakRadius());
-  if (m_fitPropertyBrowser->convolveMembers()) {
-    fitAlgorithm->setProperty("ConvolveMembers", true);
-    fitAlgorithm->setProperty("OutputCompositeMembers", true);
-  } else {
-    fitAlgorithm->setProperty("OutputCompositeMembers", m_fitPropertyBrowser->outputCompositeMembers());
-  }
-
-  if (m_fittingModel->getFittingMode() == FittingMode::SEQUENTIAL) {
-    fitAlgorithm->setProperty("FitType", m_fitPropertyBrowser->fitType());
-  }
-  fitAlgorithm->setProperty("OutputFitStatus", true);
-}
-
 /*
  * Runs the specified fit algorithm and calls the algorithmComplete
  * method of this fit analysis tab once completed.
@@ -535,27 +303,15 @@ void FitTab::runSingleFit(IAlgorithm_sptr fitAlgorithm) {
 }
 
 void FitTab::setupFit(IAlgorithm_sptr fitAlgorithm) {
-  setAlgorithmProperties(fitAlgorithm);
+  auto properties = m_fitPropertyBrowser->fitProperties(m_fittingModel->getFittingMode());
   m_fittingAlgorithm = fitAlgorithm;
-  m_batchAlgoRunner->addAlgorithm(fitAlgorithm);
+  m_batchAlgoRunner->addAlgorithm(fitAlgorithm, std::move(properties));
   connect(m_batchAlgoRunner, SIGNAL(batchComplete(bool)), this, SLOT(fitAlgorithmComplete(bool)));
 }
 
-QList<FunctionModelDataset> FitTab::getDatasets() const {
-  QList<FunctionModelDataset> datasets;
-
-  for (auto i = 0u; i < m_dataPresenter->getNumberOfWorkspaces().value; ++i) {
-    WorkspaceID workspaceID{i};
-
-    auto const name = m_fittingModel->getWorkspace(workspaceID)->getName();
-    datasets.append(FunctionModelDataset(QString::fromStdString(name), m_dataPresenter->getSpectra(workspaceID)));
-  }
-  return datasets;
-}
-
 void FitTab::updateDataReferences() {
   m_fitPropertyBrowser->updateFunctionBrowserData(static_cast<int>(m_dataPresenter->getNumberOfDomains()),
-                                                  getDatasets(), m_dataPresenter->getQValuesForData(),
+                                                  m_dataPresenter->getDatasets(), m_dataPresenter->getQValuesForData(),
                                                   m_dataPresenter->getResolutionsForFit());
   setModelFitFunction();
 }
@@ -565,14 +321,17 @@ void FitTab::updateDataReferences() {
  * enabled/disabled.
  */
 void FitTab::updateResultOptions() {
-  const bool isFit = m_fittingModel->isPreviouslyFit(getSelectedDataIndex(), getSelectedSpectrum());
+  const bool isFit = m_fittingModel->isPreviouslyFit(m_plotPresenter->getActiveWorkspaceID(),
+                                                     m_plotPresenter->getActiveWorkspaceIndex());
   if (isFit)
-    m_outOptionsPresenter->setResultWorkspace(getResultWorkspace());
+    m_outOptionsPresenter->setResultWorkspace(m_fittingModel->getResultWorkspace());
   m_outOptionsPresenter->setPlotEnabled(isFit);
   m_outOptionsPresenter->setEditResultEnabled(isFit);
   m_outOptionsPresenter->setSaveEnabled(isFit);
 }
 
+std::string FitTab::tabName() const { return m_parentWidget->windowTitle().toStdString(); }
+
 void FitTab::handleDataChanged() {
   updateDataReferences();
   m_fittingModel->removeFittingData();
@@ -617,33 +376,12 @@ void FitTab::handleBackgroundChanged(double value) {
   m_plotPresenter->updateGuess();
 }
 
-void FitTab::respondToFunctionChanged() {
+void FitTab::handleFunctionChanged() {
   setModelFitFunction();
   m_fittingModel->removeFittingData();
   m_plotPresenter->updatePlots();
   m_plotPresenter->updateFit();
-  m_fittingModel->setFitTypeString(getFitTypeString());
-}
-
-std::string FitTab::getFitTypeString() const {
-  auto const multiDomainFunction = m_fittingModel->getFitFunction();
-  if (!multiDomainFunction || multiDomainFunction->nFunctions() == 0) {
-    return "NoCurrentFunction";
-  }
-
-  std::string fitType{""};
-  for (auto const &fitFunctionName : FUNCTION_STRINGS) {
-    auto occurances = getNumberOfCustomFunctions(fitFunctionName.first);
-    if (occurances > 0) {
-      fitType += std::to_string(occurances) + fitFunctionName.second;
-    }
-  }
-
-  if (getNumberOfCustomFunctions("DeltaFunction") > 0) {
-    fitType += "Delta";
-  }
-
-  return fitType;
+  m_fittingModel->updateFitTypeString();
 }
 
 } // namespace Inelastic
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.h
index 1be9c8bd2402..cc9593bb4511 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTab.h
@@ -16,18 +16,9 @@
 #include "InelasticFitPropertyBrowser.h"
 #include "ui_FitTab.h"
 
-#include "MantidQtWidgets/Common/FunctionModelDataset.h"
-
-#include <boost/optional.hpp>
-
-#include <QtCore>
-
 #include <memory>
 #include <optional>
-#include <type_traits>
 
-#include <QList>
-#include <QPair>
 #include <QString>
 
 namespace MantidQt {
@@ -37,6 +28,7 @@ namespace Inelastic {
 class MANTIDQT_INELASTIC_DLL IFitTab {
 public:
   // Used by FitDataPresenter
+  virtual std::string tabName() const = 0;
   virtual void handleDataAdded(IAddWorkspaceDialog const *dialog) = 0;
   virtual void handleDataChanged() = 0;
   virtual void handleDataRemoved() = 0;
@@ -53,13 +45,16 @@ class MANTIDQT_INELASTIC_DLL IFitTab {
 
   // Used by FitOutputOptionsPresenter
   virtual void handlePlotSelectedSpectra() = 0;
+
+  // Used by InelasticFitPropertyBrowser
+  virtual void handleFunctionChanged() = 0;
 };
 
 class MANTIDQT_INELASTIC_DLL FitTab : public IndirectTab, public IFitTab {
   Q_OBJECT
 
 public:
-  FitTab(std::string const &tabName, bool const hasResolution, QWidget *parent = nullptr);
+  FitTab(QWidget *parent, std::string const &tabName);
   virtual ~FitTab() override = default;
 
   template <typename FittingModel> void setupFittingModel() { m_fittingModel = std::make_unique<FittingModel>(); }
@@ -74,7 +69,9 @@ class MANTIDQT_INELASTIC_DLL FitTab : public IndirectTab, public IFitTab {
     m_uiForm->dockArea->m_fitPropertyBrowser->init();
     m_uiForm->dockArea->m_fitPropertyBrowser->setHiddenProperties(hiddenProperties);
     m_fitPropertyBrowser = m_uiForm->dockArea->m_fitPropertyBrowser;
-    setConvolveMembers(convolveMembers);
+    m_fitPropertyBrowser->setConvolveMembers(convolveMembers);
+    if (convolveMembers)
+      m_fitPropertyBrowser->setOutputCompositeMembers(true);
   }
 
   template <typename FitDataView> void setupFitDataView() {
@@ -90,18 +87,7 @@ class MANTIDQT_INELASTIC_DLL FitTab : public IndirectTab, public IFitTab {
   void setupPlotView(std::optional<std::pair<double, double>> const &xPlotBounds = std::nullopt);
   void subscribeFitBrowserToDataPresenter();
 
-  WorkspaceID getSelectedDataIndex() const;
-  WorkspaceIndex getSelectedSpectrum() const;
-  bool isRangeCurrentlySelected(WorkspaceID workspaceID, WorkspaceIndex spectrum) const;
-  size_t getNumberOfCustomFunctions(const std::string &functionName) const;
-  void setConvolveMembers(bool convolveMembers);
-
-  static size_t getNumberOfSpecificFunctionContained(const std::string &functionName,
-                                                     const IFunction *compositeFunction);
-
-  std::string getTabName() const noexcept { return m_tabName; }
-  bool hasResolution() const noexcept { return m_hasResolution; }
-  void setFileExtensionsByName(bool filter);
+  std::string tabName() const override;
 
   void handleDataAdded(IAddWorkspaceDialog const *dialog) override;
   void handleDataChanged() override;
@@ -120,73 +106,44 @@ public slots:
   void handleStartXChanged(double startX) override;
   void handleEndXChanged(double endX) override;
 
-protected:
-  FittingModel *getFittingModel() const;
-  void run() override;
-  void setSampleWSSuffixes(const QStringList &suffices);
-  void setSampleFBSuffixes(const QStringList &suffices);
-  void setResolutionWSSuffixes(const QStringList &suffices);
-  void setResolutionFBSuffixes(const QStringList &suffices);
-  void setSampleSuffixes(std::string const &tab, bool filter);
-  void setResolutionSuffixes(std::string const &tab, bool filter);
-
-  void setAlgorithmProperties(const Mantid::API::IAlgorithm_sptr &fitAlgorithm) const;
-  void runFitAlgorithm(Mantid::API::IAlgorithm_sptr fitAlgorithm);
-  void runSingleFit(Mantid::API::IAlgorithm_sptr fitAlgorithm);
-  void setupFit(Mantid::API::IAlgorithm_sptr fitAlgorithm);
-
-  void setRunIsRunning(bool running);
-  void setRunEnabled(bool enable);
-  void setEditResultVisible(bool visible);
-  std::unique_ptr<FitDataPresenter> m_dataPresenter;
-  std::unique_ptr<FitPlotPresenter> m_plotPresenter;
-  std::unique_ptr<FittingModel> m_fittingModel;
-  InelasticFitPropertyBrowser *m_fitPropertyBrowser{nullptr};
-  WorkspaceID m_activeWorkspaceID;
-  WorkspaceIndex m_activeSpectrumIndex;
+  void handleFunctionChanged() override;
 
-  std::unique_ptr<Ui::FitTab> m_uiForm;
+private slots:
+  void updateFitOutput(bool error);
+  void updateSingleFitOutput(bool error);
+  void fitAlgorithmComplete(bool error);
 
 private:
   void setup() override;
   bool validate() override;
-  void connectFitPropertyBrowser();
-  void plotSelectedSpectra(std::vector<SpectrumToPlot> const &spectra);
-  void plotSpectrum(std::string const &workspaceName, std::size_t const &index);
-  std::string getOutputBasename() const;
-  Mantid::API::WorkspaceGroup_sptr getResultWorkspace() const;
-  std::vector<std::string> getFitParameterNames() const;
-  QList<MantidWidgets::FunctionModelDataset> getDatasets() const;
+  void run() override;
+
+  void runFitAlgorithm(Mantid::API::IAlgorithm_sptr fitAlgorithm);
+  void runSingleFit(Mantid::API::IAlgorithm_sptr fitAlgorithm);
+  void setupFit(Mantid::API::IAlgorithm_sptr fitAlgorithm);
+
   void enableFitButtons(bool enable);
   void enableOutputOptions(bool enable);
   void setPDFWorkspace(std::string const &workspaceName);
+  void setModelFitFunction();
+
   void updateParameterEstimationData();
-  std::string getFitTypeString() const;
+  void updateFitStatus();
+  void updateDataReferences();
+  void updateResultOptions();
+  void updateFitBrowserParameterValues(const std::unordered_map<std::string, ParameterValue> &parameters =
+                                           std::unordered_map<std::string, ParameterValue>());
+  void updateFitBrowserParameterValuesFromAlg();
 
-  std::string m_tabName;
-  bool m_hasResolution;
+  std::unique_ptr<Ui::FitTab> m_uiForm;
 
+  std::unique_ptr<FitDataPresenter> m_dataPresenter;
+  std::unique_ptr<FittingModel> m_fittingModel;
+  std::unique_ptr<FitPlotPresenter> m_plotPresenter;
   std::unique_ptr<FitOutputOptionsPresenter> m_outOptionsPresenter;
-  Mantid::API::IAlgorithm_sptr m_fittingAlgorithm;
+  InelasticFitPropertyBrowser *m_fitPropertyBrowser;
 
-protected slots:
-  void setModelFitFunction();
-  void setModelStartX(double startX);
-  void setModelEndX(double endX);
-  void updateFitOutput(bool error);
-  void updateSingleFitOutput(bool error);
-  void fitAlgorithmComplete(bool error);
-  void singleFit();
-  void executeFit();
-  void updateParameterValues();
-  void updateParameterValues(const std::unordered_map<std::string, ParameterValue> &parameters);
-  void updateFitBrowserParameterValues(const std::unordered_map<std::string, ParameterValue> &parameters =
-                                           std::unordered_map<std::string, ParameterValue>());
-  void updateFitBrowserParameterValuesFromAlg();
-  void updateFitStatus();
-  void updateDataReferences();
-  void updateResultOptions();
-  void respondToFunctionChanged();
+  Mantid::API::IAlgorithm_sptr m_fittingAlgorithm;
 };
 
 } // namespace Inelastic
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTabConstants.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTabConstants.h
index 6eea73c572cb..0f6ac088a20a 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FitTabConstants.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FitTabConstants.h
@@ -49,7 +49,6 @@ static const auto FUNCTION_STRINGS =
 
 namespace MSDFit {
 static const auto TAB_NAME = "MSDFit";
-static const auto HAS_RESOLUTION = false;
 static const auto HIDDEN_PROPS =
     std::vector<std::string>({"CreateOutput", "LogValue", "PassWSIndexToFunction", "ConvolveMembers",
                               "OutputCompositeMembers", "OutputWorkspace", "Output", "PeakRadius", "PlotParameter"});
@@ -65,7 +64,6 @@ static const auto ALL_FITS =
 
 namespace IqtFit {
 static const auto TAB_NAME = "IqtFit";
-static const auto HAS_RESOLUTION = false;
 static const auto HIDDEN_PROPS =
     std::vector<std::string>({"CreateOutput", "LogValue", "PassWSIndexToFunction", "ConvolveMembers",
                               "OutputCompositeMembers", "OutputWorkspace", "Output", "PeakRadius", "PlotParameter"});
@@ -80,7 +78,6 @@ inline auto templateSubTypes() {
 
 namespace ConvFit {
 static const auto TAB_NAME = "ConvFit";
-static const auto HAS_RESOLUTION = true;
 static const auto HIDDEN_PROPS = std::vector<std::string>(
     {"CreateOutput", "LogValue", "PassWSIndexToFunction", "OutputWorkspace", "Output", "PeakRadius", "PlotParameter"});
 
@@ -95,7 +92,6 @@ inline auto templateSubTypes() {
 
 namespace FqFit {
 static const auto TAB_NAME = "FQFit";
-static const auto HAS_RESOLUTION = false;
 static const auto HIDDEN_PROPS =
     std::vector<std::string>({"CreateOutput", "LogValue", "PassWSIndexToFunction", "ConvolveMembers",
                               "OutputCompositeMembers", "OutputWorkspace", "Output", "PeakRadius", "PlotParameter"});
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.cpp
index a6e3f620b1dd..2ab0f9cdd942 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.cpp
@@ -7,6 +7,7 @@
 #include "FittingModel.h"
 #include "FitDataModel.h"
 #include "FitOutput.h"
+#include "FitTabConstants.h"
 
 #include "MantidAPI/AlgorithmManager.h"
 #include "MantidAPI/AnalysisDataService.h"
@@ -278,6 +279,27 @@ void setFirstBackground(IFunction_sptr function, double value) {
   firstFunctionWithParameter(function, "Background", "A0")->setParameter("A0", value);
 }
 
+size_t getNumberOfSpecificFunctionContained(const std::string &functionName, const IFunction *compositeFunction) {
+  assert(compositeFunction);
+
+  if (compositeFunction->nFunctions() == 0) {
+    return compositeFunction->name() == functionName ? 1 : 0;
+  }
+
+  size_t count{0};
+  for (size_t i{0}; i < compositeFunction->nFunctions(); i++) {
+    count += getNumberOfSpecificFunctionContained(functionName, compositeFunction->getFunction(i).get());
+  }
+  return count;
+}
+
+size_t getNumberOfCustomFunctions(MultiDomainFunction_const_sptr const &fittingFunction,
+                                  const std::string &functionName) {
+  if (fittingFunction && fittingFunction->nFunctions() > 0)
+    return getNumberOfSpecificFunctionContained(functionName, fittingFunction->getFunction(0).get());
+  return 0u;
+}
+
 } // namespace
 
 namespace MantidQt::CustomInterfaces::Inelastic {
@@ -289,6 +311,11 @@ FittingModel::FittingModel()
     : m_fitDataModel(std::make_unique<FitDataModel>()), m_previousModelSelected(false),
       m_fittingMode(FittingMode::SEQUENTIAL), m_fitOutput(std::make_unique<FitOutput>()) {}
 
+void FittingModel::validate(UserInputValidator &validator) const {
+  if (auto const invalidFunction = isInvalidFunction())
+    validator.addErrorMessage(QString::fromStdString(*invalidFunction));
+}
+
 // Functions that interact with FitDataModel
 
 void FittingModel::addDefaultParameters() { m_defaultParameters.emplace_back(createDefaultParameters(WorkspaceID{0})); }
@@ -313,7 +340,25 @@ WorkspaceID FittingModel::getNumberOfWorkspaces() const { return m_fitDataModel-
 bool FittingModel::isMultiFit() const { return m_fitDataModel->getNumberOfWorkspaces().value > 1; }
 
 // Other Functions
-void FittingModel::setFitTypeString(const std::string &fitType) { m_fitString = fitType; }
+void FittingModel::updateFitTypeString() {
+  auto const multiDomainFunction = getFitFunction();
+  if (!multiDomainFunction || multiDomainFunction->nFunctions() == 0) {
+    m_fitString = "NoCurrentFunction";
+    return;
+  }
+
+  m_fitString.clear();
+  for (auto const &fitFunctionName : FUNCTION_STRINGS) {
+    auto occurances = getNumberOfCustomFunctions(multiDomainFunction, fitFunctionName.first);
+    if (occurances > 0) {
+      m_fitString += std::to_string(occurances) + fitFunctionName.second;
+    }
+  }
+
+  if (getNumberOfCustomFunctions(multiDomainFunction, "DeltaFunction") > 0) {
+    m_fitString += "Delta";
+  }
+}
 
 std::string FittingModel::createOutputName(const std::string &fitMode, const std::string &workspaceName,
                                            const std::string &spectra) const {
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.h
index a91ee7bf6cad..17afd61a0a01 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FittingModel.h
@@ -15,6 +15,7 @@
 #include "MantidAPI/IAlgorithm.h"
 #include "MantidAPI/WorkspaceGroup.h"
 #include "MantidQtWidgets/Common/FunctionModelSpectra.h"
+#include "MantidQtWidgets/Common/UserInputValidator.h"
 
 #include <boost/optional.hpp>
 #include <boost/variant.hpp>
@@ -45,6 +46,8 @@ class MANTIDQT_INELASTIC_DLL FittingModel : public IFittingModel {
   FittingModel();
   virtual ~FittingModel() = default;
 
+  void validate(UserInputValidator &validator) const;
+
   // Functions that interact with FitDataModel
   void clearWorkspaces() override;
   Mantid::API::MatrixWorkspace_sptr getWorkspace(WorkspaceID workspaceID) const override;
@@ -77,7 +80,7 @@ class MANTIDQT_INELASTIC_DLL FittingModel : public IFittingModel {
   void setFittingMode(FittingMode mode) override;
   FittingMode getFittingMode() const override;
 
-  void setFitTypeString(const std::string &fitType) override;
+  void updateFitTypeString() override;
   boost::optional<ResultLocationNew> getResultLocation(WorkspaceID workspaceID, WorkspaceIndex spectrum) const override;
   Mantid::API::WorkspaceGroup_sptr getResultWorkspace() const override;
   Mantid::API::WorkspaceGroup_sptr getResultGroup() const override;
@@ -94,6 +97,9 @@ class MANTIDQT_INELASTIC_DLL FittingModel : public IFittingModel {
 
   IFitDataModel *getFitDataModel() override;
 
+  // Used for testing purposes
+  [[nodiscard]] inline std::string getFitString() const noexcept { return m_fitString; }
+
 protected:
   std::string createOutputName(const std::string &fitMode, const std::string &workspaceName,
                                const std::string &spectra) const;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.cpp
index 0a287ec71542..1db0c2de559c 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.cpp
@@ -5,6 +5,8 @@
 //   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
 // SPDX - License - Identifier: GPL - 3.0 +
 #include "FqFitDataView.h"
+#include "Common/InterfaceUtils.h"
+#include "Common/SettingsHelper.h"
 #include "FqFitAddWorkspaceDialog.h"
 #include "FqFitDataPresenter.h"
 
@@ -45,9 +47,10 @@ void FqFitDataView::showAddWorkspaceDialog() {
   connect(dialog, SIGNAL(parameterTypeChanged(FqFitAddWorkspaceDialog *, const std::string &)), this,
           SLOT(notifyParameterTypeChanged(FqFitAddWorkspaceDialog *, const std::string &)));
 
+  auto tabName = m_presenter->tabName();
   dialog->setAttribute(Qt::WA_DeleteOnClose);
-  dialog->setWSSuffices(m_wsSampleSuffixes);
-  dialog->setFBSuffices(m_fbSampleSuffixes);
+  dialog->setWSSuffices(InterfaceUtils::getSampleWSSuffixes(tabName));
+  dialog->setFBSuffices(InterfaceUtils::getSampleFBSuffixes(tabName));
   dialog->updateSelectedSpectra();
   dialog->show();
 }
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.h
index a45bf43db83e..cc93f6c491de 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FqFitDataView.h
@@ -23,11 +23,11 @@ Presenter for a table of convolution fitting data.
 class MANTIDQT_INELASTIC_DLL FqFitDataView : public FitDataView {
   Q_OBJECT
 public:
-  FqFitDataView(QWidget *parent = nullptr);
+  FqFitDataView(QWidget *parent);
   void addTableEntry(size_t row, FitDataRow newRow) override;
 
 protected:
-  FqFitDataView(const QStringList &headers, QWidget *parent = nullptr);
+  FqFitDataView(const QStringList &headers, QWidget *parent);
 
 protected slots:
   void showAddWorkspaceDialog() override;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.cpp
index a28301bbeef2..fa4817ce5f99 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.cpp
@@ -72,9 +72,11 @@ void FunctionTemplatePresenter::setDatasets(const QList<MantidWidgets::FunctionM
   m_model->setDatasets(datasets);
 }
 
-QStringList FunctionTemplatePresenter::getDatasetNames() const { return m_model->getDatasetNames(); }
+std::vector<std::string> FunctionTemplatePresenter::getDatasetNames() const { return m_model->getDatasetNames(); }
 
-QStringList FunctionTemplatePresenter::getDatasetDomainNames() const { return m_model->getDatasetDomainNames(); }
+std::vector<std::string> FunctionTemplatePresenter::getDatasetDomainNames() const {
+  return m_model->getDatasetDomainNames();
+}
 
 void FunctionTemplatePresenter::setErrorsEnabled(bool enabled) { m_view->setErrorsEnabled(enabled); }
 
@@ -123,8 +125,7 @@ void FunctionTemplatePresenter::handleEditLocalParameter(std::string const &para
   QList<bool> fixes;
   QStringList ties;
   QStringList constraints;
-  const int n = domainNames.size();
-  for (auto i = 0; i < n; ++i) {
+  for (auto i = 0; i < static_cast<int>(domainNames.size()); ++i) {
     const double value = getLocalParameterValue(parameterName, i);
     values.push_back(value);
     const bool fixed = isLocalParameterFixed(parameterName, i);
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.h
index 8a2d248c59f3..d3662e91aaae 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplatePresenter.h
@@ -81,8 +81,8 @@ class MANTIDQT_INELASTIC_DLL FunctionTemplatePresenter : public ITemplatePresent
 protected:
   virtual void updateView() = 0;
 
-  QStringList getDatasetNames() const;
-  QStringList getDatasetDomainNames() const;
+  std::vector<std::string> getDatasetNames() const;
+  std::vector<std::string> getDatasetDomainNames() const;
 
   void setLocalParameterValue(std::string const &parameterName, int i, double value);
   void setLocalParameterTie(std::string const &parameterName, int i, std::string const &tie);
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.cpp
index 02bace145a54..26a99c1e39f5 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.cpp
@@ -165,7 +165,8 @@ void FunctionTemplateView::updateMultiDatasetParameters(const ITableWorkspace &t
 void FunctionTemplateView::updateParameters(const IFunction &fun) { m_presenter->updateParameters(fun); }
 
 void FunctionTemplateView::openEditLocalParameterDialog(std::string const &parameterName,
-                                                        QStringList const &datasetNames, QStringList const &domainNames,
+                                                        std::vector<std::string> const &datasetNames,
+                                                        std::vector<std::string> const &domainNames,
                                                         QList<double> const &values, QList<bool> const &fixes,
                                                         QStringList const &ties, QStringList const &constraints) {
   auto dialog =
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.h
index e47d14a35b5e..312e122e48a1 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/FunctionTemplateView.h
@@ -15,6 +15,9 @@
 #include "MantidQtWidgets/Common/FunctionModelDataset.h"
 #include "MantidQtWidgets/Common/IndexTypes.h"
 
+#include <string>
+#include <vector>
+
 #include <QList>
 #include <QMap>
 #include <QPair>
@@ -84,8 +87,8 @@ class MANTIDQT_INELASTIC_DLL FunctionTemplateView : public QWidget {
 
   void emitFunctionStructureChanged() { emit functionStructureChanged(); }
 
-  void openEditLocalParameterDialog(std::string const &parameterName, QStringList const &datasetNames,
-                                    QStringList const &domainNames, QList<double> const &values,
+  void openEditLocalParameterDialog(std::string const &parameterName, std::vector<std::string> const &datasetNames,
+                                    std::vector<std::string> const &domainNames, QList<double> const &values,
                                     QList<bool> const &fixes, QStringList const &ties, QStringList const &constraints);
 
 signals:
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.cpp
index ea5eba5eb293..530dc666e775 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.cpp
@@ -64,9 +64,11 @@ void MultiFunctionTemplateModel::setDatasets(const QList<FunctionModelDataset> &
   m_model->setDatasets(datasets);
 }
 
-QStringList MultiFunctionTemplateModel::getDatasetNames() const { return m_model->getDatasetNames(); }
+std::vector<std::string> MultiFunctionTemplateModel::getDatasetNames() const { return m_model->getDatasetNames(); }
 
-QStringList MultiFunctionTemplateModel::getDatasetDomainNames() const { return m_model->getDatasetDomainNames(); }
+std::vector<std::string> MultiFunctionTemplateModel::getDatasetDomainNames() const {
+  return m_model->getDatasetDomainNames();
+}
 
 void MultiFunctionTemplateModel::setCurrentDomainIndex(int i) { m_model->setCurrentDomainIndex(i); }
 
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.h b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.h
index 129b241a8b43..e4bd8794ab5e 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/FunctionBrowser/MultiFunctionTemplateModel.h
@@ -47,8 +47,8 @@ class MANTIDQT_INELASTIC_DLL MultiFunctionTemplateModel : public IFunctionModel
   void setNumberDomains(int) override;
   int getNumberDomains() const override;
   void setDatasets(const QList<FunctionModelDataset> &datasets) override;
-  QStringList getDatasetNames() const override;
-  QStringList getDatasetDomainNames() const override;
+  std::vector<std::string> getDatasetNames() const override;
+  std::vector<std::string> getDatasetDomainNames() const override;
   void setCurrentDomainIndex(int i) override;
   int currentDomainIndex() const override;
 
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataModel.h b/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataModel.h
index 6a130aa4a8cf..02abec0cc0db 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataModel.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataModel.h
@@ -11,6 +11,7 @@
 #include "DllConfig.h"
 #include "FitData.h"
 #include "MantidAPI/MatrixWorkspace.h"
+#include "MantidQtWidgets/Common/FunctionModelDataset.h"
 #include "MantidQtWidgets/Common/FunctionModelSpectra.h"
 #include "MantidQtWidgets/Common/IndexTypes.h"
 
@@ -33,6 +34,7 @@ class MANTIDQT_INELASTIC_DLL IFitDataModel {
   virtual bool hasWorkspace(std::string const &workspaceName) const = 0;
   virtual Mantid::API::MatrixWorkspace_sptr getWorkspace(WorkspaceID workspaceID) const = 0;
   virtual FunctionModelSpectra getSpectra(WorkspaceID workspaceID) const = 0;
+  virtual FunctionModelDataset getDataset(WorkspaceID workspaceID) const = 0;
   virtual WorkspaceID getNumberOfWorkspaces() const = 0;
   virtual size_t getNumberOfSpectra(WorkspaceID workspaceID) const = 0;
   virtual size_t getNumberOfDomains() const = 0;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataView.h b/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataView.h
index 63b2b86d1b8b..b46d14eda549 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataView.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/IFitDataView.h
@@ -36,7 +36,7 @@ class MANTIDQT_INELASTIC_DLL IFitDataView {
   virtual QTableWidget *getDataTable() const = 0;
   virtual bool isTableEmpty() const = 0;
 
-  virtual UserInputValidator &validate(UserInputValidator &validator) = 0;
+  virtual void validate(UserInputValidator &validator) = 0;
   virtual void addTableEntry(size_t row, FitDataRow newRow) = 0;
   virtual void updateNumCellEntry(double numEntry, size_t row, size_t column) = 0;
   virtual int getColumnIndexFromName(std::string const &ColName) = 0;
@@ -45,11 +45,6 @@ class MANTIDQT_INELASTIC_DLL IFitDataView {
   virtual QModelIndexList getSelectedIndexes() const = 0;
   virtual bool dataColumnContainsText(std::string const &columnText) const = 0;
 
-  virtual void setSampleWSSuffices(const QStringList &suffices) = 0;
-  virtual void setSampleFBSuffices(const QStringList &suffices) = 0;
-  virtual void setResolutionWSSuffices(const QStringList &suffices) = 0;
-  virtual void setResolutionFBSuffices(const QStringList &suffices) = 0;
-
   virtual void displayWarning(std::string const &warning) = 0;
 };
 } // namespace Inelastic
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/IFittingModel.h b/qt/scientific_interfaces/Inelastic/QENSFitting/IFittingModel.h
index e025df3ee7a2..84efebf727c0 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/IFittingModel.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/IFittingModel.h
@@ -57,7 +57,7 @@ class MANTIDQT_INELASTIC_DLL IFittingModel {
   virtual void setFittingMode(FittingMode mode) = 0;
   virtual FittingMode getFittingMode() const = 0;
 
-  virtual void setFitTypeString(const std::string &fitType) = 0;
+  virtual void updateFitTypeString() = 0;
   virtual boost::optional<ResultLocationNew> getResultLocation(WorkspaceID workspaceID,
                                                                WorkspaceIndex spectrum) const = 0;
   virtual Mantid::API::WorkspaceGroup_sptr getResultWorkspace() const = 0;
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.cpp
index 5001545e969c..9b2b69464e96 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.cpp
@@ -11,6 +11,7 @@
 #include "FunctionBrowser/SingleFunctionTemplateView.h"
 
 #include "MantidAPI/AlgorithmManager.h"
+#include "MantidAPI/AlgorithmProperties.h"
 #include "MantidAPI/FrameworkManager.h"
 #include "MantidAPI/ITableWorkspace.h"
 #include "MantidAPI/MatrixWorkspace.h"
@@ -249,6 +250,30 @@ std::string InelasticFitPropertyBrowser::fitType() const {
   return m_fitOptionsBrowser->getProperty("FitType").toStdString();
 }
 
+std::unique_ptr<Mantid::API::AlgorithmRuntimeProps>
+InelasticFitPropertyBrowser::fitProperties(FittingMode const &fittingMode) const {
+  auto properties = std::make_unique<Mantid::API::AlgorithmRuntimeProps>();
+  Mantid::API::AlgorithmProperties::update("Minimizer", minimizer(true), *properties);
+  Mantid::API::AlgorithmProperties::update("MaxIterations", maxIterations(), *properties);
+  Mantid::API::AlgorithmProperties::update("PeakRadius", getPeakRadius(), *properties);
+  Mantid::API::AlgorithmProperties::update("CostFunction", costFunction(), *properties);
+  Mantid::API::AlgorithmProperties::update("IgnoreInvalidData", ignoreInvalidData(), *properties);
+  Mantid::API::AlgorithmProperties::update("EvaluationType", fitEvaluationType(), *properties);
+  Mantid::API::AlgorithmProperties::update("PeakRadius", getPeakRadius(), *properties);
+  Mantid::API::AlgorithmProperties::update("CostFunction", costFunction(), *properties);
+  Mantid::API::AlgorithmProperties::update("ConvolveMembers", convolveMembers(), *properties);
+  if (convolveMembers()) {
+    Mantid::API::AlgorithmProperties::update("OutputCompositeMembers", true, *properties);
+  } else {
+    Mantid::API::AlgorithmProperties::update("OutputCompositeMembers", outputCompositeMembers(), *properties);
+  }
+  if (fittingMode == FittingMode::SEQUENTIAL) {
+    Mantid::API::AlgorithmProperties::update("FitType", fitType(), *properties);
+  }
+  Mantid::API::AlgorithmProperties::update("OutputFitStatus", true, *properties);
+  return properties;
+}
+
 int InelasticFitPropertyBrowser::getNumberOfDatasets() const {
   return isFullFunctionBrowserActive() ? m_functionBrowser->getNumberOfDatasets()
                                        : m_templatePresenter->getNumberOfDatasets();
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.h b/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.h
index d3c29a0f08d1..35a800ed00c0 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/InelasticFitPropertyBrowser.h
@@ -8,6 +8,7 @@
 
 #include "DllConfig.h"
 #include "FunctionBrowser/ITemplatePresenter.h"
+#include "MantidAPI/AlgorithmRuntimeProps.h"
 #include "MantidAPI/IFunction_fwd.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
 #include "MantidAPI/MatrixWorkspace_fwd.h"
@@ -68,6 +69,7 @@ class MANTIDQT_INELASTIC_DLL InelasticFitPropertyBrowser : public QDockWidget, p
   std::string fitEvaluationType() const;
   std::string fitType() const;
   bool ignoreInvalidData() const;
+  std::unique_ptr<Mantid::API::AlgorithmRuntimeProps> fitProperties(FittingMode const &fittingMode) const;
   void updateParameters(const IFunction &fun);
   void updateMultiDatasetParameters(const IFunction &fun);
   void updateMultiDatasetParameters(const ITableWorkspace &params);
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.cpp
index 435d8929691f..a702f60891a2 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.cpp
@@ -25,12 +25,6 @@ QENSFitting::QENSFitting(QWidget *parent)
   m_tabs.emplace(FQ_FIT, tabFactory->makeFqFitTab(FQ_FIT));
 }
 
-void QENSFitting::applySettings(std::map<std::string, QVariant> const &settings) {
-  for (auto tab = m_tabs.begin(); tab != m_tabs.end(); ++tab) {
-    tab->second->setFileExtensionsByName(settings.at("RestrictInput").toBool());
-  }
-}
-
 /**
  * Initialised the layout of the interface.  MUST be called.
  */
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.h b/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.h
index a20c794d262b..b594261424cf 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.h
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/QENSFitting.h
@@ -50,8 +50,6 @@ private slots:
 private:
   std::string documentationPage() const override;
 
-  void applySettings(std::map<std::string, QVariant> const &settings) override;
-
   /// UI form containing all Qt elements.
   Ui::QENSFitting m_uiForm;
   /// The settings group
diff --git a/qt/scientific_interfaces/Inelastic/QENSFitting/TabFactory.cpp b/qt/scientific_interfaces/Inelastic/QENSFitting/TabFactory.cpp
index f39f996db95c..743084f25124 100644
--- a/qt/scientific_interfaces/Inelastic/QENSFitting/TabFactory.cpp
+++ b/qt/scientific_interfaces/Inelastic/QENSFitting/TabFactory.cpp
@@ -39,7 +39,7 @@ namespace MantidQt::CustomInterfaces::Inelastic {
 TabFactory::TabFactory(QTabWidget *tabWidget) : m_tabWidget(tabWidget) {}
 
 FitTab *TabFactory::makeMSDFitTab(int const index) const {
-  auto tab = new FitTab(MSDFit::TAB_NAME, MSDFit::HAS_RESOLUTION, m_tabWidget->widget(index));
+  auto tab = new FitTab(m_tabWidget->widget(index), MSDFit::TAB_NAME);
   tab->setupFittingModel<MSDFitModel>();
   tab->setupFitPropertyBrowser<SingleFunctionTemplateView, SingleFunctionTemplatePresenter, MSDFunctionModel>(
       MSDFit::HIDDEN_PROPS);
@@ -51,7 +51,7 @@ FitTab *TabFactory::makeMSDFitTab(int const index) const {
 }
 
 FitTab *TabFactory::makeIqtFitTab(int const index) const {
-  auto tab = new FitTab(IqtFit::TAB_NAME, IqtFit::HAS_RESOLUTION, m_tabWidget->widget(index));
+  auto tab = new FitTab(m_tabWidget->widget(index), IqtFit::TAB_NAME);
   tab->setupFittingModel<IqtFitModel>();
   auto browserCustomizations = packBrowserCustomizations(IqtFit::templateSubTypes());
   tab->setupFitPropertyBrowser<MultiFunctionTemplateView, MultiFunctionTemplatePresenter, IqtFunctionTemplateModel>(
@@ -64,7 +64,7 @@ FitTab *TabFactory::makeIqtFitTab(int const index) const {
 }
 
 FitTab *TabFactory::makeConvFitTab(int const index) const {
-  auto tab = new FitTab(ConvFit::TAB_NAME, ConvFit::HAS_RESOLUTION, m_tabWidget->widget(index));
+  auto tab = new FitTab(m_tabWidget->widget(index), ConvFit::TAB_NAME);
   tab->setupFittingModel<ConvFitModel>();
   auto browserCustomizations = packBrowserCustomizations(ConvFit::templateSubTypes());
   tab->setupFitPropertyBrowser<MultiFunctionTemplateView, MultiFunctionTemplatePresenter, ConvFunctionTemplateModel>(
@@ -77,7 +77,7 @@ FitTab *TabFactory::makeConvFitTab(int const index) const {
 }
 
 FitTab *TabFactory::makeFqFitTab(int const index) const {
-  auto tab = new FitTab(FqFit::TAB_NAME, FqFit::HAS_RESOLUTION, m_tabWidget->widget(index));
+  auto tab = new FitTab(m_tabWidget->widget(index), FqFit::TAB_NAME);
   tab->setupFittingModel<FqFitModel>();
   tab->setupFitPropertyBrowser<SingleFunctionTemplateView, SingleFunctionTemplatePresenter, FqFunctionModel>(
       FqFit::HIDDEN_PROPS);
diff --git a/qt/scientific_interfaces/Inelastic/test/Common/InterfaceUtilsTest.h b/qt/scientific_interfaces/Inelastic/test/Common/InterfaceUtilsTest.h
index 804ae30020fa..14470b5a723c 100644
--- a/qt/scientific_interfaces/Inelastic/test/Common/InterfaceUtilsTest.h
+++ b/qt/scientific_interfaces/Inelastic/test/Common/InterfaceUtilsTest.h
@@ -15,7 +15,7 @@
 #include <cxxtest/TestSuite.h>
 
 using namespace Mantid::API;
-using namespace Mantid::IndirectFitDataCreationHelper;
+using namespace MantidQt::CustomInterfaces;
 using namespace MantidQt::CustomInterfaces::InterfaceUtils;
 
 class InterfaceUtilsTest : public CxxTest::TestSuite {
@@ -28,7 +28,19 @@ class InterfaceUtilsTest : public CxxTest::TestSuite {
     TS_ASSERT_EQUALS(getInterfaceProperty("Empty", "EXTENSIONS", "all"), "");
   }
 
-  void test_get_FB_WS_suffixes_function_returns_proper_interface_suffixes() {
+  void test_get_FB_WS_suffixes_when_restrict_data_is_off() {
+    auto mockRestrictInputDataByName = []() { return false; };
+    InterfaceUtils::restrictInputDataByName = mockRestrictInputDataByName;
+
+    // There are many similar functions in the interface, this test will try only one pair of such functions
+    TS_ASSERT_EQUALS(getResolutionWSSuffixes("Iqt"), QStringList({""}));
+    TS_ASSERT_EQUALS(getResolutionFBSuffixes("Iqt"), QStringList({".nxs"}));
+  }
+
+  void test_get_FB_WS_suffixes_when_restrict_data_is_on() {
+    auto mockRestrictInputDataByName = []() { return true; };
+    InterfaceUtils::restrictInputDataByName = mockRestrictInputDataByName;
+
     // There are many similar functions in the interface, this test will try only one pair of such functions
     TS_ASSERT_EQUALS(getResolutionWSSuffixes("Iqt"), QStringList({"_res", "_red", "_sqw"}));
     TS_ASSERT_EQUALS(getResolutionFBSuffixes("Iqt"), QStringList({"_res.nxs", "_red.nxs", "_sqw.nxs"}));
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/CMakeLists.txt b/qt/scientific_interfaces/Inelastic/test/QENSFitting/CMakeLists.txt
index 2bf6d1c6ccaa..263231a6ceac 100644
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/CMakeLists.txt
+++ b/qt/scientific_interfaces/Inelastic/test/QENSFitting/CMakeLists.txt
@@ -4,7 +4,6 @@ set(TEST_FILES
     ConvFitModelTest.h
     ConvFitDataPresenterTest.h
     ConvFunctionTemplateModelTest.h
-    FitTabTest.h
     FqFitDataPresenterTest.h
     FqFitModelTest.h
     FitDataPresenterTest.h
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitDataPresenterTest.h b/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitDataPresenterTest.h
index 66f7cfe41a36..a33c14155081 100644
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitDataPresenterTest.h
+++ b/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitDataPresenterTest.h
@@ -163,38 +163,6 @@ class FitDataPresenterTest : public CxxTest::TestSuite {
     m_presenter->setResolution("WorkspaceName");
   }
 
-  void test_that_setSampleWSSuffices_will_set_the_sample_workspace_suffices_in_the_view() {
-    QStringList const suffices{"suffix1", "suffix2"};
-
-    EXPECT_CALL(*m_view, setSampleWSSuffices(suffices)).Times(Exactly(1));
-
-    m_presenter->setSampleWSSuffices(suffices);
-  }
-
-  void test_that_setSampleFBSuffices_will_set_the_sample_file_suffices_in_the_view() {
-    QStringList const suffices{"suffix1", "suffix2"};
-
-    EXPECT_CALL(*m_view, setSampleFBSuffices(suffices)).Times(Exactly(1));
-
-    m_presenter->setSampleFBSuffices(suffices);
-  }
-
-  void test_that_setResolutionWSSuffices_will_set_the_Resolution_workspace_suffices_in_the_view() {
-    QStringList const suffices{"suffix1", "suffix2"};
-
-    EXPECT_CALL(*m_view, setResolutionWSSuffices(suffices)).Times(Exactly(1));
-
-    m_presenter->setResolutionWSSuffices(suffices);
-  }
-
-  void test_that_setResolutionFBSuffices_will_set_the_Resolution_file_suffices_in_the_view() {
-    QStringList const suffices{"suffix1", "suffix2"};
-
-    EXPECT_CALL(*m_view, setResolutionFBSuffices(suffices)).Times(Exactly(1));
-
-    m_presenter->setResolutionFBSuffices(suffices);
-  }
-
   void test_getResolutionsForFit_calls_from_model() {
     std::vector<std::pair<std::string, size_t>> resolutions = {{"string", 1}};
     EXPECT_CALL(*m_model, getResolutionsForFit()).Times(Exactly(1)).WillOnce(Return(resolutions));
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitTabTest.h b/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitTabTest.h
deleted file mode 100644
index 8d7967b7780c..000000000000
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FitTabTest.h
+++ /dev/null
@@ -1,54 +0,0 @@
-// Mantid Repository : https://github.com/mantidproject/mantid
-//
-// Copyright &copy; 2019 ISIS Rutherford Appleton Laboratory UKRI,
-//   NScD Oak Ridge National Laboratory, European Spallation Source,
-//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
-// SPDX - License - Identifier: GPL - 3.0 +
-#pragma once
-
-#include "QENSFitting/FitTab.h"
-
-#include "MantidAPI/FunctionFactory.h"
-#include <cxxtest/TestSuite.h>
-#include <gmock/gmock.h>
-
-using namespace MantidQt::CustomInterfaces::Inelastic;
-
-class FitTabTest : public CxxTest::TestSuite {
-public:
-  static FitTabTest *createSuite() { return new FitTabTest(); }
-
-  static void destroySuite(FitTabTest *suite) { delete suite; }
-
-  void test_that_single_function_correctly_identified() {
-    std::string functionName = "ExpDecay";
-    auto fitFunction = Mantid::API::FunctionFactory::Instance().createFunction(functionName);
-    auto occurances = FitTab::getNumberOfSpecificFunctionContained(functionName, fitFunction.get());
-    TS_ASSERT_EQUALS(occurances, 1);
-  }
-
-  void test_that_single_layer_composite_function_handled_correctly() {
-    std::string functionName = "name=ExpDecay;name=StretchExp";
-    auto fitFunction = Mantid::API::FunctionFactory::Instance().createInitialized(functionName);
-    auto occurances = FitTab::getNumberOfSpecificFunctionContained("ExpDecay", fitFunction.get());
-    auto stretchOccurances = FitTab::getNumberOfSpecificFunctionContained("StretchExp", fitFunction.get());
-    TS_ASSERT_EQUALS(occurances, 1);
-    TS_ASSERT_EQUALS(stretchOccurances, 1);
-  }
-
-  void test_that_no_matched_name_is_correct() {
-    std::string functionName = "name=ExpDecay;name=StretchExp";
-    auto fitFunction = Mantid::API::FunctionFactory::Instance().createInitialized(functionName);
-    auto occurances = FitTab::getNumberOfSpecificFunctionContained("NotHere", fitFunction.get());
-    TS_ASSERT_EQUALS(occurances, 0);
-  }
-
-  void test_that_multi_layer_composite_function_handled_correctly() {
-    std::string functionName = "name=ExpDecay;name=ExpDecay;(composite="
-                               "ProductFunction,NumDeriv=false;name=ExpDecay;"
-                               "name=ExpDecay)";
-    auto fitFunction = Mantid::API::FunctionFactory::Instance().createInitialized(functionName);
-    auto occurances = FitTab::getNumberOfSpecificFunctionContained("ExpDecay", fitFunction.get());
-    TS_ASSERT_EQUALS(occurances, 4);
-  }
-};
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FittingModelTest.h b/qt/scientific_interfaces/Inelastic/test/QENSFitting/FittingModelTest.h
index 297d0e7f31c0..d4540b90c6fc 100644
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/FittingModelTest.h
+++ b/qt/scientific_interfaces/Inelastic/test/QENSFitting/FittingModelTest.h
@@ -376,9 +376,9 @@ class FittingModelTest : public CxxTest::TestSuite {
     TS_ASSERT_EQUALS(m_model->getFittingMode(), simultaneous);
   }
 
-  void test_setFitTypeString_sets_member() {
+  void test_updateFitTypeString_does_not_throw() {
     addWorkspaceToModel("Workspace1", 3, "0-2");
-    TS_ASSERT_THROWS_NOTHING(m_model->setFitTypeString("TestString"));
+    TS_ASSERT_THROWS_NOTHING(m_model->updateFitTypeString());
   }
 
   void test_getResultLocation_returns_none_when_out_of_index() {
@@ -435,6 +435,46 @@ class FittingModelTest : public CxxTest::TestSuite {
     TS_ASSERT_EQUALS(m_model->getOutputBasename(), outputString);
   }
 
+  void test_that_single_function_correctly_identified() {
+    auto const function = getFunction("composite=MultiDomainFunction,NumDeriv=true;(composite=Convolution,"
+                                      "NumDeriv=true,FixResolution=true,$domains=i;name=Resolution,"
+                                      "WorkspaceIndex=0,X=(),Y=();(name=ExpDecay,Height=1,Lifetime=1;));");
+    m_model->setFitFunction(function);
+    m_model->updateFitTypeString();
+    TS_ASSERT_EQUALS("1E", m_model->getFitString());
+  }
+
+  void test_that_single_layer_composite_function_handled_correctly() {
+    auto const function = getFunction("composite=MultiDomainFunction,NumDeriv=true;(composite=Convolution,"
+                                      "NumDeriv=true,FixResolution=true,$domains=i;name=Resolution,"
+                                      "WorkspaceIndex=0,X=(),Y=();(name=ExpDecay,Height=1,Lifetime=1;name=StretchExp,"
+                                      "Height=1,Lifetime=1,Stretching=1;));");
+    m_model->setFitFunction(function);
+    m_model->updateFitTypeString();
+    auto const fitString = m_model->getFitString();
+    TS_ASSERT(fitString.find("1E") != std::string::npos);
+    TS_ASSERT(fitString.find("1S") != std::string::npos);
+  }
+
+  void test_that_no_matched_name_is_correct() {
+    auto const function = getFunction("composite=MultiDomainFunction,NumDeriv=true;(composite=Convolution,"
+                                      "NumDeriv=true,FixResolution=true,$domains=i;name=Resolution,"
+                                      "WorkspaceIndex=0,X=(),Y=();(name=ExpDecayMuon,A=1,Lambda=1;));");
+    m_model->setFitFunction(function);
+    m_model->updateFitTypeString();
+    TS_ASSERT_EQUALS("", m_model->getFitString());
+  }
+
+  void test_that_multi_layer_composite_function_handled_correctly() {
+    auto const function = getFunction(
+        "composite=MultiDomainFunction,NumDeriv=true;(composite=Convolution,"
+        "NumDeriv=true,FixResolution=true,$domains=i;name=Resolution,"
+        "WorkspaceIndex=0,X=(),Y=();(name=ExpDecay,Height=1,Lifetime=1;name=ExpDecay,Height=1,Lifetime=1;));");
+    m_model->setFitFunction(function);
+    m_model->updateFitTypeString();
+    TS_ASSERT_EQUALS("2E", m_model->getFitString());
+  }
+
 private:
   void addWorkspaceToModel(std::string workspaceName, int numberOfSpectra, std::string const &spectra) {
     SetUpADSWithWorkspace ads(workspaceName, createWorkspace(numberOfSpectra));
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/InelasticFitPropertyBrowserTest.h b/qt/scientific_interfaces/Inelastic/test/QENSFitting/InelasticFitPropertyBrowserTest.h
index 6d91cb80cc44..67b75e9e50c8 100644
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/InelasticFitPropertyBrowserTest.h
+++ b/qt/scientific_interfaces/Inelastic/test/QENSFitting/InelasticFitPropertyBrowserTest.h
@@ -219,7 +219,7 @@ class InelasticFitPropertyBrowserTest : public CxxTest::TestSuite {
       WorkspaceID workspaceID{i};
 
       auto const name = "wsName" + std::to_string(i);
-      datasets.append(FunctionModelDataset(QString::fromStdString(name), FunctionModelSpectra("0")));
+      datasets.append(FunctionModelDataset(name, FunctionModelSpectra("0")));
     }
     std::vector<double> qValues = {0.0, 1.0};
     std::vector<std::pair<std::string, size_t>> fitResolutions(1, std::make_pair<std::string, size_t>("resWS", 0));
diff --git a/qt/scientific_interfaces/Inelastic/test/QENSFitting/MockObjects.h b/qt/scientific_interfaces/Inelastic/test/QENSFitting/MockObjects.h
index 718c4eda87d5..232da1a96a71 100644
--- a/qt/scientific_interfaces/Inelastic/test/QENSFitting/MockObjects.h
+++ b/qt/scientific_interfaces/Inelastic/test/QENSFitting/MockObjects.h
@@ -41,6 +41,7 @@ class MockFitTab : public IFitTab {
 public:
   virtual ~MockFitTab() = default;
 
+  MOCK_CONST_METHOD0(tabName, std::string());
   MOCK_METHOD1(handleDataAdded, void(MantidQt::MantidWidgets::IAddWorkspaceDialog const *dialog));
   MOCK_METHOD0(handleDataChanged, void());
   MOCK_METHOD0(handleDataRemoved, void());
@@ -55,6 +56,8 @@ class MockFitTab : public IFitTab {
   MOCK_METHOD1(handleBackgroundChanged, void(double background));
 
   MOCK_METHOD0(handlePlotSelectedSpectra, void());
+
+  MOCK_METHOD0(handleFunctionChanged, void());
 };
 
 class MockFitPlotView : public IFitPlotView {
@@ -204,6 +207,7 @@ class MockFitDataModel : public IFitDataModel {
   MOCK_METHOD2(setSpectra, void(FunctionModelSpectra &&spectra, WorkspaceID workspaceID));
   MOCK_METHOD2(setSpectra, void(const FunctionModelSpectra &spectra, WorkspaceID workspaceID));
   MOCK_CONST_METHOD1(getSpectra, FunctionModelSpectra(WorkspaceID workspaceID));
+  MOCK_CONST_METHOD1(getDataset, FunctionModelDataset(WorkspaceID workspaceID));
   MOCK_CONST_METHOD1(getSpectrum, size_t(FitDomainIndex index));
   MOCK_CONST_METHOD1(getNumberOfSpectra, size_t(WorkspaceID workspaceID));
 
@@ -247,8 +251,7 @@ class MockFitDataView : public IFitDataView {
 
   MOCK_CONST_METHOD0(getDataTable, QTableWidget *());
   MOCK_CONST_METHOD0(isTableEmpty, bool());
-  MOCK_METHOD1(validate, MantidQt::CustomInterfaces::UserInputValidator &(
-                             MantidQt::CustomInterfaces::UserInputValidator &validator));
+  MOCK_METHOD1(validate, void(MantidQt::CustomInterfaces::UserInputValidator &validator));
   MOCK_METHOD2(addTableEntry, void(size_t row, FitDataRow newRow));
   MOCK_METHOD3(updateNumCellEntry, void(double numEntry, size_t row, size_t column));
   MOCK_METHOD1(getColumnIndexFromName, int(std::string const &ColName));
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/EditLocalParameterDialog.h b/qt/widgets/common/inc/MantidQtWidgets/Common/EditLocalParameterDialog.h
index 96a960c74173..0224dc3fcfad 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/EditLocalParameterDialog.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/EditLocalParameterDialog.h
@@ -12,6 +12,8 @@
 #include "ui_EditLocalParameterDialog.h"
 
 #include <memory>
+#include <string>
+#include <vector>
 
 #include <QDialog>
 
@@ -28,9 +30,9 @@ class FunctionMultiDomainPresenter;
 class EXPORT_OPT_MANTIDQT_COMMON EditLocalParameterDialog : public MantidQt::API::MantidDialog {
   Q_OBJECT
 public:
-  EditLocalParameterDialog(QWidget *parent, const std::string &parName, const QStringList &datasetNames,
-                           const QStringList &datasetDomainNames, const QList<double> &values, const QList<bool> &fixes,
-                           const QStringList &ties, const QStringList &constraints);
+  EditLocalParameterDialog(QWidget *parent, const std::string &parName, const std::vector<std::string> &datasetNames,
+                           const std::vector<std::string> &datasetDomainNames, const QList<double> &values,
+                           const QList<bool> &fixes, const QStringList &ties, const QStringList &constraints);
 
   std::string getParameterName() const { return m_parName; }
   QList<double> getValues() const;
@@ -66,7 +68,8 @@ private slots:
   void setAllValuesToLog();
 
 private:
-  void doSetup(const std::string &parName, const QStringList &datasetDomains, const QStringList &datasetDomainNames);
+  void doSetup(const std::string &parName, const std::vector<std::string> &datasetDomains,
+               const std::vector<std::string> &datasetDomainNames);
   bool eventFilter(QObject *obj, QEvent *ev) override;
   void showContextMenu();
   void redrawCells();
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionBrowser.h b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionBrowser.h
index 00180d8393cd..db560df2e18e 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionBrowser.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionBrowser.h
@@ -77,9 +77,9 @@ class EXPORT_OPT_MANTIDQT_COMMON FunctionBrowser : public QWidget, public IFunct
   /// Get the number of datasets
   int getNumberOfDatasets() const override;
   /// Get the names of datasets
-  QStringList getDatasetNames() const override;
+  std::vector<std::string> getDatasetNames() const override;
   /// Get the names of the dataset domains
-  QStringList getDatasetDomainNames() const override;
+  std::vector<std::string> getDatasetDomainNames() const override;
   /// Get value of a local parameter
   double getLocalParameterValue(std::string const &parameterName, int i) const override;
   /// Set value of a local parameter
@@ -137,12 +137,12 @@ public slots:
 
   // Handling of multiple datasets
   void setNumberOfDatasets(int n) override;
-  void setDatasets(const QStringList &datasetNames) override;
+  void setDatasets(const std::vector<std::string> &datasetNames) override;
   void setDatasets(const QList<FunctionModelDataset> &datasets) override;
   void resetLocalParameters();
   void setCurrentDataset(int i) override;
   void removeDatasets(const QList<int> &indices);
-  void addDatasets(const QStringList &names);
+  void addDatasets(const std::vector<std::string> &names);
 
 protected:
   std::unique_ptr<FunctionMultiDomainPresenter> m_presenter;
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModel.h b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModel.h
index 07cfde6fbd14..5d08f3296993 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModel.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModel.h
@@ -44,12 +44,12 @@ class EXPORT_OPT_MANTIDQT_COMMON FunctionModel : public IFunctionModel {
   IFunction_sptr getSingleFunction(int index) const override;
   IFunction_sptr getCurrentFunction() const override;
   void setNumberDomains(int) override;
-  void setDatasets(const QStringList &datasetNames);
+  void setDatasets(const std::vector<std::string> &datasetNames);
   void setDatasets(const QList<FunctionModelDataset> &datasets) override;
-  void addDatasets(const QStringList &datasetNames);
+  void addDatasets(const std::vector<std::string> &datasetNames);
   void removeDatasets(QList<int> &indices);
-  QStringList getDatasetNames() const override;
-  QStringList getDatasetDomainNames() const override;
+  std::vector<std::string> getDatasetNames() const override;
+  std::vector<std::string> getDatasetDomainNames() const override;
   int getNumberDomains() const override;
   int currentDomainIndex() const override;
   void setCurrentDomainIndex(int) override;
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModelDataset.h b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModelDataset.h
index c64dfa72a907..9b1eb705a60e 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModelDataset.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionModelDataset.h
@@ -9,9 +9,8 @@
 #include "DllOption.h"
 #include "MantidQtWidgets/Common/FunctionModelSpectra.h"
 
-#include <QList>
-#include <QString>
-#include <QStringList>
+#include <string>
+#include <vector>
 
 namespace MantidQt {
 namespace MantidWidgets {
@@ -24,15 +23,15 @@ namespace MantidWidgets {
  */
 struct EXPORT_OPT_MANTIDQT_COMMON FunctionModelDataset {
 public:
-  FunctionModelDataset(QString workspaceName, FunctionModelSpectra spectra);
+  FunctionModelDataset(std::string workspaceName, FunctionModelSpectra spectra);
 
-  inline QString datasetName() const noexcept { return m_workspaceName; }
-  QStringList domainNames() const;
+  inline std::string datasetName() const noexcept { return m_workspaceName; }
+  std::vector<std::string> domainNames() const;
 
   inline std::size_t numberOfSpectra() const noexcept { return m_spectra.size().value; }
 
 private:
-  QString m_workspaceName;
+  std::string m_workspaceName;
   FunctionModelSpectra m_spectra;
 };
 
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionMultiDomainPresenter.h b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionMultiDomainPresenter.h
index 240f3a6bf150..fac1b21c7a86 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionMultiDomainPresenter.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/FunctionMultiDomainPresenter.h
@@ -49,11 +49,11 @@ class EXPORT_OPT_MANTIDQT_COMMON FunctionMultiDomainPresenter : public QObject {
   void clearErrors();
   boost::optional<std::string> currentFunctionIndex() const;
   void setNumberOfDatasets(int);
-  void setDatasets(const QStringList &datasetNames);
+  void setDatasets(const std::vector<std::string> &datasetNames);
   void setDatasets(const QList<FunctionModelDataset> &datasets);
-  void addDatasets(const QStringList &datasetNames);
-  QStringList getDatasetNames() const;
-  QStringList getDatasetDomainNames() const;
+  void addDatasets(const std::vector<std::string> &datasetNames);
+  std::vector<std::string> getDatasetNames() const;
+  std::vector<std::string> getDatasetDomainNames() const;
   int getNumberOfDatasets() const;
   int getCurrentDataset() const;
   void setCurrentDataset(int);
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionBrowser.h b/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionBrowser.h
index 52231494c855..71da09d2d9bb 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionBrowser.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionBrowser.h
@@ -12,10 +12,12 @@
 #include "MantidAPI/IFunction_fwd.h"
 #include "MantidAPI/ITableWorkspace_fwd.h"
 
+#include <string>
+#include <vector>
+
 #include <QList>
 #include <QPair>
 #include <QString>
-#include <QStringList>
 
 namespace MantidQt {
 namespace MantidWidgets {
@@ -34,7 +36,7 @@ class EXPORT_OPT_MANTIDQT_COMMON IFunctionBrowser {
   virtual void clearErrors() = 0;
   virtual void setFunction(std::string const &funStr) = 0;
   virtual void setNumberOfDatasets(int n) = 0;
-  virtual void setDatasets(const QStringList &datasetNames) = 0;
+  virtual void setDatasets(const std::vector<std::string> &datasetNames) = 0;
   virtual void setDatasets(const QList<FunctionModelDataset> &datasets) = 0;
   virtual Mantid::API::IFunction_sptr getGlobalFunction() = 0;
   virtual void updateMultiDatasetParameters(const Mantid::API::IFunction &fun) = 0;
@@ -43,8 +45,8 @@ class EXPORT_OPT_MANTIDQT_COMMON IFunctionBrowser {
   virtual double getLocalParameterValue(std::string const &parameterName, int i) const = 0;
   virtual std::string getLocalParameterTie(std::string const &parameterName, int i) const = 0;
   virtual int getNumberOfDatasets() const = 0;
-  virtual QStringList getDatasetNames() const = 0;
-  virtual QStringList getDatasetDomainNames() const = 0;
+  virtual std::vector<std::string> getDatasetNames() const = 0;
+  virtual std::vector<std::string> getDatasetDomainNames() const = 0;
   virtual void setLocalParameterValue(std::string const &parameterName, int i, double value) = 0;
   virtual void setLocalParameterFixed(std::string const &parameterName, int i, bool fixed) = 0;
   virtual void setLocalParameterTie(std::string const &parameterName, int i, std::string const &tie) = 0;
diff --git a/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionModel.h b/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionModel.h
index 9d61514fcbeb..e987ac328c2b 100644
--- a/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionModel.h
+++ b/qt/widgets/common/inc/MantidQtWidgets/Common/IFunctionModel.h
@@ -46,8 +46,8 @@ class EXPORT_OPT_MANTIDQT_COMMON IFunctionModel {
   virtual IFunction_sptr getCurrentFunction() const = 0;
   virtual void setNumberDomains(int) = 0;
   virtual void setDatasets(const QList<FunctionModelDataset> &datasets) = 0;
-  virtual QStringList getDatasetNames() const = 0;
-  virtual QStringList getDatasetDomainNames() const = 0;
+  virtual std::vector<std::string> getDatasetNames() const = 0;
+  virtual std::vector<std::string> getDatasetDomainNames() const = 0;
   virtual int getNumberDomains() const = 0;
   virtual int currentDomainIndex() const = 0;
   virtual void setCurrentDomainIndex(int) = 0;
diff --git a/qt/widgets/common/src/EditLocalParameterDialog.cpp b/qt/widgets/common/src/EditLocalParameterDialog.cpp
index e99f263f5ce6..d986dc6ce6d6 100644
--- a/qt/widgets/common/src/EditLocalParameterDialog.cpp
+++ b/qt/widgets/common/src/EditLocalParameterDialog.cpp
@@ -8,6 +8,7 @@
 
 #include "MantidQtWidgets/Common/FunctionMultiDomainPresenter.h"
 #include "MantidQtWidgets/Common/LocalParameterItemDelegate.h"
+#include "MantidQtWidgets/Common/ParseKeyValueString.h"
 
 #include <QClipboard>
 #include <QMenu>
@@ -35,10 +36,10 @@ namespace MantidQt::MantidWidgets {
  * @param constraints :: [input] Parameter constraints.
  */
 EditLocalParameterDialog::EditLocalParameterDialog(QWidget *parent, const std::string &parName,
-                                                   const QStringList &datasetNames,
-                                                   const QStringList &datasetDomainNames, const QList<double> &values,
-                                                   const QList<bool> &fixes, const QStringList &ties,
-                                                   const QStringList &constraints)
+                                                   const std::vector<std::string> &datasetNames,
+                                                   const std::vector<std::string> &datasetDomainNames,
+                                                   const QList<double> &values, const QList<bool> &fixes,
+                                                   const QStringList &ties, const QStringList &constraints)
     : MantidDialog(parent), m_parName(parName), m_values(values), m_fixes(fixes), m_ties(std::move(ties)),
       m_constraints(std::move(constraints)) {
   assert(values.size() == datasetDomainNames.size());
@@ -58,9 +59,9 @@ EditLocalParameterDialog::EditLocalParameterDialog(QWidget *parent, const std::s
  * @param datasetNames :: [input] Names of workspaces being fitted.
  * @param datasetDomainNames :: [input] Names given to the domains being fitted.
  */
-void EditLocalParameterDialog::doSetup(const std::string &parName, const QStringList &datasetNames,
-                                       const QStringList &datasetDomainNames) {
-  m_logFinder = std::make_unique<LogValueFinder>(datasetNames);
+void EditLocalParameterDialog::doSetup(const std::string &parName, const std::vector<std::string> &datasetNames,
+                                       const std::vector<std::string> &datasetDomainNames) {
+  m_logFinder = std::make_unique<LogValueFinder>(stdVectorToQStringList(datasetNames));
   // Populate list of logs
   auto *logCombo = m_uiForm.logValueSelector->getLogComboBox();
   for (const auto &logName : m_logFinder->getLogNames()) {
@@ -78,7 +79,7 @@ void EditLocalParameterDialog::doSetup(const std::string &parName, const QString
     m_uiForm.tableWidget->insertRow(i);
     auto cell = new QTableWidgetItem(makeNumber(m_values[i]));
     m_uiForm.tableWidget->setItem(i, valueColumn, cell);
-    auto headerItem = new QTableWidgetItem(datasetDomainNames[i]);
+    auto headerItem = new QTableWidgetItem(QString::fromStdString(datasetDomainNames[i]));
     m_uiForm.tableWidget->setVerticalHeaderItem(i, headerItem);
     cell = new QTableWidgetItem("");
     auto flags = cell->flags();
diff --git a/qt/widgets/common/src/FitScriptGeneratorView.cpp b/qt/widgets/common/src/FitScriptGeneratorView.cpp
index 4058a1bd435b..9e7ca183733b 100644
--- a/qt/widgets/common/src/FitScriptGeneratorView.cpp
+++ b/qt/widgets/common/src/FitScriptGeneratorView.cpp
@@ -358,8 +358,8 @@ void FitScriptGeneratorView::openEditLocalParameterDialog(
     std::vector<std::string> const &domainNames, std::vector<double> const &values, std::vector<bool> const &fixes,
     std::vector<std::string> const &ties, std::vector<std::string> const &constraints) {
   m_editLocalParameterDialog = new EditLocalParameterDialog(
-      this, parameter, stdVectorToQStringList(workspaceNames), stdVectorToQStringList(domainNames),
-      convertToQList(values), convertToQList(fixes), stdVectorToQStringList(ties), stdVectorToQStringList(constraints));
+      this, parameter, workspaceNames, domainNames, convertToQList(values), convertToQList(fixes),
+      stdVectorToQStringList(ties), stdVectorToQStringList(constraints));
 
   connect(m_editLocalParameterDialog, SIGNAL(finished(int)), this, SLOT(onEditLocalParameterFinished(int)));
 
diff --git a/qt/widgets/common/src/FunctionBrowser.cpp b/qt/widgets/common/src/FunctionBrowser.cpp
index 0c3841544122..39b306e1f390 100644
--- a/qt/widgets/common/src/FunctionBrowser.cpp
+++ b/qt/widgets/common/src/FunctionBrowser.cpp
@@ -133,10 +133,10 @@ bool FunctionBrowser::hasFunction() const { return m_presenter->hasFunction(); }
 int FunctionBrowser::getNumberOfDatasets() const { return m_presenter->getNumberOfDatasets(); }
 
 /// Get the names of datasets
-QStringList FunctionBrowser::getDatasetNames() const { return m_presenter->getDatasetNames(); }
+std::vector<std::string> FunctionBrowser::getDatasetNames() const { return m_presenter->getDatasetNames(); }
 
 /// Get the names of the dataset domains
-QStringList FunctionBrowser::getDatasetDomainNames() const { return m_presenter->getDatasetDomainNames(); }
+std::vector<std::string> FunctionBrowser::getDatasetDomainNames() const { return m_presenter->getDatasetDomainNames(); }
 
 /// Set new number of the datasets
 /// @param n :: New value for the number of datasets.
@@ -145,7 +145,9 @@ void FunctionBrowser::setNumberOfDatasets(int n) { m_presenter->setNumberOfDatas
 /// Sets the datasets being fitted. They will be displayed by the
 /// local parameter editing dialog.
 /// @param datasetNames :: Names of the datasets
-void FunctionBrowser::setDatasets(const QStringList &datasetNames) { m_presenter->setDatasets(datasetNames); }
+void FunctionBrowser::setDatasets(const std::vector<std::string> &datasetNames) {
+  m_presenter->setDatasets(datasetNames);
+}
 
 /// Sets the datasets being fitted. They will be displayed by the
 /// local parameter editing dialog.
@@ -185,7 +187,7 @@ void FunctionBrowser::removeDatasets(const QList<int> &indices) { m_presenter->r
 
 /// Add some datasets to those already set.
 /// @param names :: A list of names for the new datasets.
-void FunctionBrowser::addDatasets(const QStringList &names) { m_presenter->addDatasets(names); }
+void FunctionBrowser::addDatasets(const std::vector<std::string> &names) { m_presenter->addDatasets(names); }
 
 /// Return the multidomain function for multi-dataset fitting
 IFunction_sptr FunctionBrowser::getGlobalFunction() { return m_presenter->getFitFunction(); }
diff --git a/qt/widgets/common/src/FunctionModel.cpp b/qt/widgets/common/src/FunctionModel.cpp
index c2abdb4711d5..5ea4f4e37167 100644
--- a/qt/widgets/common/src/FunctionModel.cpp
+++ b/qt/widgets/common/src/FunctionModel.cpp
@@ -273,7 +273,7 @@ void FunctionModel::setNumberDomains(int nDomains) {
 /// Sets the datasets based on their workspace names. This assumes there is only
 /// a single spectrum in the workspaces being fitted.
 /// @param datasetNames :: Names of the workspaces to be fitted.
-void FunctionModel::setDatasets(const QStringList &datasetNames) {
+void FunctionModel::setDatasets(const std::vector<std::string> &datasetNames) {
   QList<FunctionModelDataset> datasets;
   for (const auto &datasetName : datasetNames)
     datasets.append(FunctionModelDataset(datasetName, FunctionModelSpectra("0")));
@@ -293,7 +293,7 @@ void FunctionModel::setDatasets(const QList<FunctionModelDataset> &datasets) {
 /// Adds datasets based on their workspace names. This assumes there is only
 /// a single spectrum in the added workspaces.
 /// @param datasetNames :: Names of the workspaces to be added.
-void FunctionModel::addDatasets(const QStringList &datasetNames) {
+void FunctionModel::addDatasets(const std::vector<std::string> &datasetNames) {
   for (const auto &datasetName : datasetNames)
     m_datasets.append(FunctionModelDataset(datasetName, FunctionModelSpectra("0")));
 
@@ -324,24 +324,26 @@ void FunctionModel::removeDatasets(QList<int> &indices) {
 /// Returns the workspace names of the datasets. If a dataset has N spectra,
 /// then the workspace name is multiplied by N. This is required for
 /// EditLocalParameterDialog.
-QStringList FunctionModel::getDatasetNames() const {
-  QStringList datasetNames;
+std::vector<std::string> FunctionModel::getDatasetNames() const {
+  std::vector<std::string> allDatasetNames;
   for (const auto &dataset : m_datasets)
     for (auto i = 0u; i < dataset.numberOfSpectra(); ++i) {
       UNUSED_ARG(i);
-      datasetNames << dataset.datasetName();
+      allDatasetNames.emplace_back(dataset.datasetName());
     }
-  return datasetNames;
+  return allDatasetNames;
 }
 
 /// Returns names for the domains of each dataset. If a dataset has multiple
 /// spectra, then a domain name will include the spectrum number of a domain in
 /// a workspace. This is required for EditLocalParameterDialog.
-QStringList FunctionModel::getDatasetDomainNames() const {
-  QStringList domainNames;
-  for (const auto &dataset : m_datasets)
-    domainNames << dataset.domainNames();
-  return domainNames;
+std::vector<std::string> FunctionModel::getDatasetDomainNames() const {
+  std::vector<std::string> allDomainNames;
+  for (const auto &dataset : m_datasets) {
+    auto const domainNames = dataset.domainNames();
+    allDomainNames.insert(allDomainNames.end(), domainNames.cbegin(), domainNames.cend());
+  }
+  return allDomainNames;
 }
 
 int FunctionModel::getNumberDomains() const { return static_cast<int>(m_numberDomains); }
@@ -499,7 +501,7 @@ void FunctionModel::checkDatasets() {
   if (numberOfDomains(m_datasets) != static_cast<int>(m_numberDomains)) {
     m_datasets.clear();
     for (auto i = 0u; i < m_numberDomains; ++i)
-      m_datasets.append(FunctionModelDataset(QString::number(i), FunctionModelSpectra("0")));
+      m_datasets.append(FunctionModelDataset(std::to_string(i), FunctionModelSpectra("0")));
   }
 }
 
diff --git a/qt/widgets/common/src/FunctionModelDataset.cpp b/qt/widgets/common/src/FunctionModelDataset.cpp
index e3f7ba2dcebd..27d1aebf0fee 100644
--- a/qt/widgets/common/src/FunctionModelDataset.cpp
+++ b/qt/widgets/common/src/FunctionModelDataset.cpp
@@ -11,7 +11,7 @@
 
 namespace MantidQt::MantidWidgets {
 
-FunctionModelDataset::FunctionModelDataset(QString workspaceName, FunctionModelSpectra spectra)
+FunctionModelDataset::FunctionModelDataset(std::string workspaceName, FunctionModelSpectra spectra)
     : m_workspaceName(std::move(workspaceName)), m_spectra(std::move(spectra)) {}
 
 /**
@@ -20,16 +20,16 @@ FunctionModelDataset::FunctionModelDataset(QString workspaceName, FunctionModelS
  *
  * @returns the names given to each domain (i.e. spectrum) in this dataset.
  */
-QStringList FunctionModelDataset::domainNames() const {
+std::vector<std::string> FunctionModelDataset::domainNames() const {
   const auto numOfSpectra = m_spectra.size().value;
   if (numOfSpectra == 0u)
     throw std::runtime_error("There are no spectra in this Dataset.");
   if (numOfSpectra == 1u)
-    return QStringList(m_workspaceName);
+    return std::vector<std::string>{m_workspaceName};
   else {
-    QStringList domains;
-    for (const auto &spectrum : m_spectra)
-      domains << m_workspaceName + " (" + QString::number(spectrum.value) + ")";
+    std::vector<std::string> domains;
+    std::transform(m_spectra.begin(), m_spectra.end(), std::back_inserter(domains),
+                   [&](auto const &spectrum) { return m_workspaceName + " (" + std::to_string(spectrum.value) + ")"; });
     return domains;
   }
 }
diff --git a/qt/widgets/common/src/FunctionMultiDomainPresenter.cpp b/qt/widgets/common/src/FunctionMultiDomainPresenter.cpp
index 777be7527c3e..21d5bd6b298e 100644
--- a/qt/widgets/common/src/FunctionMultiDomainPresenter.cpp
+++ b/qt/widgets/common/src/FunctionMultiDomainPresenter.cpp
@@ -117,17 +117,23 @@ boost::optional<std::string> FunctionMultiDomainPresenter::currentFunctionIndex(
 
 void FunctionMultiDomainPresenter::setNumberOfDatasets(int n) { m_model->setNumberDomains(n); }
 
-void FunctionMultiDomainPresenter::setDatasets(const QStringList &datasetNames) { m_model->setDatasets(datasetNames); }
+void FunctionMultiDomainPresenter::setDatasets(const std::vector<std::string> &datasetNames) {
+  m_model->setDatasets(datasetNames);
+}
 
 void FunctionMultiDomainPresenter::setDatasets(const QList<FunctionModelDataset> &datasets) {
   m_model->setDatasets(datasets);
 }
 
-void FunctionMultiDomainPresenter::addDatasets(const QStringList &datasetNames) { m_model->addDatasets(datasetNames); }
+void FunctionMultiDomainPresenter::addDatasets(const std::vector<std::string> &datasetNames) {
+  m_model->addDatasets(datasetNames);
+}
 
-QStringList FunctionMultiDomainPresenter::getDatasetNames() const { return m_model->getDatasetNames(); }
+std::vector<std::string> FunctionMultiDomainPresenter::getDatasetNames() const { return m_model->getDatasetNames(); }
 
-QStringList FunctionMultiDomainPresenter::getDatasetDomainNames() const { return m_model->getDatasetDomainNames(); }
+std::vector<std::string> FunctionMultiDomainPresenter::getDatasetDomainNames() const {
+  return m_model->getDatasetDomainNames();
+}
 
 int FunctionMultiDomainPresenter::getNumberOfDatasets() const { return m_model->getNumberDomains(); }
 
@@ -326,8 +332,7 @@ void FunctionMultiDomainPresenter::editLocalParameter(std::string const &paramet
   QList<bool> fixes;
   QStringList ties;
   QStringList constraints;
-  const int n = domainNames.size();
-  for (int i = 0; i < n; ++i) {
+  for (int i = 0; i < static_cast<int>(domainNames.size()); ++i) {
     const double value = getLocalParameterValue(parameterName, i);
     values.push_back(value);
     const bool fixed = isLocalParameterFixed(parameterName, i);