construct the QgsFieldCalculator dialog with the correct parent

This is necessary to ensure proper modal behaviour.

Author: SebDieBln

src/app/qgisapp.cpp

@@ -5440,7 +5440,7 @@ void QgisApp::fieldCalculator()
     return;
   }
 
-  QgsFieldCalculator calc( myLayer );
+  QgsFieldCalculator calc( myLayer, this );
   if ( calc.exec() )
   {
     mMapCanvas->refresh();

src/app/qgsattributetabledialog.cpp

@@ -551,7 +551,7 @@ void QgsAttributeTableDialog::on_mOpenFieldCalculator_clicked()
 {
   QgsAttributeTableModel* masterModel = mMainView->masterModel();
 
-  QgsFieldCalculator calc( mLayer );
+  QgsFieldCalculator calc( mLayer, this );
   if ( calc.exec() == QDialog::Accepted )
   {
     int col = masterModel->fieldCol( calc.changedAttributeId() );

src/app/qgsfieldcalculator.cpp

@@ -27,8 +27,8 @@
 #include <QMessageBox>
 #include <QSettings>
 
-QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl )
-    : QDialog()
+QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl, QWidget* parent )
+    : QDialog( parent )
     , mVectorLayer( vl )
     , mAttributeId( -1 )
 {

src/app/qgsfieldcalculator.h

@@ -26,7 +26,7 @@ class APP_EXPORT QgsFieldCalculator: public QDialog, private Ui::QgsFieldCalcula
 {
     Q_OBJECT
   public:
-    QgsFieldCalculator( QgsVectorLayer* vl );
+    QgsFieldCalculator( QgsVectorLayer* vl, QWidget* parent = nullptr );
     ~QgsFieldCalculator();
 
     int changedAttributeId() const { return mAttributeId; }

src/app/qgsfieldsproperties.cpp

@@ -762,7 +762,7 @@ void QgsFieldsProperties::on_mCalculateFieldButton_clicked()
     return;
   }
 
-  QgsFieldCalculator calc( mLayer );
+  QgsFieldCalculator calc( mLayer, this );
   calc.exec();
 }