[TD]fix lost parent on undo

src/Mod/TechDraw/Gui/MDIViewPage.cpp

@@ -76,7 +76,6 @@
 #include "Rez.h"
 #include "ViewProviderPage.h"
 
-
 using namespace TechDrawGui;
 using namespace TechDraw;
 namespace bp = boost::placeholders;
@@ -194,6 +193,7 @@ bool MDIViewPage::onMsg(const char* pMsg, const char**)
     else if (strcmp("Undo", pMsg) == 0) {
         doc->undo(1);
         Gui::Command::updateActive();
+        fixSceneDependencies();    // check QGraphicsScene item parenting
         return true;
     }
     else if (strcmp("Redo", pMsg) == 0) {
@@ -246,6 +246,14 @@ void MDIViewPage::setTabText(std::string tabText)
     }
 }
 
+// advise the page to check QGraphicsScene parent/child relationships after undo
+void MDIViewPage::fixSceneDependencies()
+{
+    if (getViewProviderPage()) {
+        getViewProviderPage()->fixSceneDependencies();
+    }
+}
+
 //**** printing routines
 
 void MDIViewPage::getPaperAttributes()

src/Mod/TechDraw/Gui/MDIViewPage.h

@@ -116,6 +116,7 @@ class TechDrawGuiExport MDIViewPage : public Gui::MDIView, public Gui::Selection
     void contextMenuEvent(QContextMenuEvent *event) override;
 
     void setScene(QGSPage* scene, QGVPage* view);
+    void fixSceneDependencies();
 
 public Q_SLOTS:
     void viewAll() override;

src/Mod/TechDraw/Gui/ViewProviderPage.cpp

@@ -60,6 +60,7 @@
 #include "QGVPage.h"
 #include "ViewProviderPageExtension.h"
 #include "ViewProviderTemplate.h"
+#include "ViewProviderViewPart.h"
 
 
 using namespace TechDrawGui;
@@ -557,3 +558,23 @@ ViewProviderPageExtension* ViewProviderPage::getVPPExtension() const
 }
 
 const char* ViewProviderPage::whoAmI() const { return m_pageName.c_str(); }
+
+
+void ViewProviderPage::fixSceneDependencies()
+{
+    App::Document* doc = getDrawPage()->getDocument();
+    std::vector<App::DocumentObject*> docObjs =
+        doc->getObjectsOfType(TechDraw::DrawViewPart::getClassTypeId());
+    for (auto& obj : docObjs) {
+        Gui::ViewProvider* vp = Gui::Application::Instance->getViewProvider(obj);
+        if (!vp) {
+            continue;// can't fix this one
+        }
+        TechDrawGui::ViewProviderViewPart* vpvp = dynamic_cast<TechDrawGui::ViewProviderViewPart*>(vp);
+        if (!vpvp) {
+            continue;// can't fix this one
+        }
+        vpvp->fixSceneDependencies();
+    }
+
+}

src/Mod/TechDraw/Gui/ViewProviderPage.h

@@ -126,6 +126,9 @@ class TechDrawGuiExport ViewProviderPage: public Gui::ViewProviderDocumentObject
 
     const char* whoAmI() const;
 
+    void fixSceneDependencies();
+
+
 protected:
     bool setEdit(int ModNum) override;
     void createMDIViewPage();

src/Mod/TechDraw/Gui/ViewProviderViewPart.cpp

@@ -52,6 +52,10 @@
 #include "QGIView.h"
 #include "TaskDetail.h"
 #include "ViewProviderViewPart.h"
+#include "ViewProviderPage.h"
+#include "QGIViewDimension.h"
+#include "QGIViewBalloon.h"
+#include "QGSPage.h"
 
 using namespace TechDrawGui;
 using namespace TechDraw;
@@ -167,6 +171,7 @@ void ViewProviderViewPart::onChanged(const App::Property* prop)
 
 void ViewProviderViewPart::attach(App::DocumentObject *pcFeat)
 {
+//    Base::Console().Message("VPVP::attach(%s)\n", pcFeat->getNameInDocument());
     TechDraw::DrawViewMulti* dvm = dynamic_cast<TechDraw::DrawViewMulti*>(pcFeat);
     TechDraw::DrawViewDetail* dvd = dynamic_cast<TechDraw::DrawViewDetail*>(pcFeat);
     if (dvm) {
@@ -222,6 +227,7 @@ std::vector<App::DocumentObject*> ViewProviderViewPart::claimChildren() const
         return std::vector<App::DocumentObject*>();
     }
 }
+
 bool ViewProviderViewPart::setEdit(int ModNum)
 {
     if (ModNum != ViewProvider::Default ) {
@@ -309,26 +315,16 @@ bool ViewProviderViewPart::onDelete(const std::vector<std::string> &)
     auto viewSection = getViewObject()->getSectionRefs();
     auto viewDetail = getViewObject()->getDetailRefs();
     auto viewLeader = getViewObject()->getLeaders();
-
-    if (!viewSection.empty()) {
-        bodyMessageStream << qApp->translate("Std_Delete",
-            "You cannot delete this view because it has a section view that would become broken.");
-        QMessageBox::warning(Gui::getMainWindow(),
-            qApp->translate("Std_Delete", "Object dependencies"), bodyMessage,
-            QMessageBox::Ok);
-        return false;
-    }
-    else if (!viewDetail.empty()) {
-        bodyMessageStream << qApp->translate("Std_Delete",
-            "You cannot delete this view because it has a detail view that would become broken.");
-        QMessageBox::warning(Gui::getMainWindow(),
-            qApp->translate("Std_Delete", "Object dependencies"), bodyMessage,
-            QMessageBox::Ok);
-        return false;
-    }
-    else if (!viewLeader.empty()) {
+    auto viewDimension = getViewObject()->getDimensions();
+    auto viewBalloon = getViewObject()->getBalloons();
+
+    if (!viewDimension.empty() ||
+             !viewBalloon.empty() ||
+             !viewSection.empty() ||
+             !viewDetail.empty() ||
+             !viewLeader.empty()) {
         bodyMessageStream << qApp->translate("Std_Delete",
-            "You cannot delete this view because it has a leader line that would become broken.");
+            "You cannot delete this view because it has one or more dependent objects that would become broken.");
         QMessageBox::warning(Gui::getMainWindow(),
             qApp->translate("Std_Delete", "Object dependencies"), bodyMessage,
             QMessageBox::Ok);
@@ -364,4 +360,31 @@ int ViewProviderViewPart::prefHighlightStyle()
     return Preferences::getPreferenceGroup("Decorations")->GetInt("HighlightStyle", 2);
 }
 
+// it can happen that Dimensions/Balloons/etc can lose their parent item if the
+// the parent is deleted, then undo is invoked.  The linkages on the App side are
+// handled by the undo mechanism, but the QGraphicsScene parentage is not reset.
+// TODO: does this need to be implemented for Leaderlines and ???? others?
+void ViewProviderViewPart::fixSceneDependencies()
+{
+//    Base::Console().Message("VPVP::fixSceneDependencies()\n");
+    auto scene = getViewProviderPage()->getQGSPage();
+    auto partQView = getQView();
+
+    auto dimensions =  getViewPart()->getDimensions();
+    for (auto& dim : dimensions) {
+        auto dimQView = dynamic_cast<QGIViewDimension *>(scene->findQViewForDocObj(dim));
+        if (dimQView && dimQView->parentItem() != partQView) {
+            // need to add the dim QView to this QGIViewPart
+            scene->addDimToParent(dimQView, partQView);
+        }
+    }
 
+    auto balloons = getViewPart()->getBalloons();
+    for (auto& bal : balloons) {
+        auto balQView = dynamic_cast<QGIViewBalloon*>(scene->findQViewForDocObj(bal));
+        if (balQView && balQView->parentItem() != partQView) {
+            // need to add the balloon QView to this QGIViewPart
+            scene->addBalloonToParent(balQView, partQView);
+        }
+    }
+}

src/Mod/TechDraw/Gui/ViewProviderViewPart.h

@@ -69,16 +69,14 @@ class TechDrawGuiExport ViewProviderViewPart : public ViewProviderDrawingView
     bool canDelete(App::DocumentObject* obj) const override;
     bool setEdit(int ModNum) override;
     bool doubleClicked(void) override;
-
-public:
     void onChanged(const App::Property *prop) override;
     void handleChangedPropertyType(Base::XMLReader &reader, const char *TypeName, App::Property * prop) override;
     App::Color prefSectionColor(void);
     App::Color prefHighlightColor(void);
     int prefHighlightStyle(void);
 
-
     std::vector<App::DocumentObject*> claimChildren(void) const override;
+    void fixSceneDependencies();
 
     TechDraw::DrawViewPart* getViewObject() const override;
     TechDraw::DrawViewPart* getViewPart() const;