Gui: add virtual method 'closed' to TaskDialog that is called when deleting a dialog

src/Gui/TaskView/TaskDialog.cpp

@@ -79,6 +79,11 @@ void TaskDialog::open()
 
 }
 
+void TaskDialog::closed()
+{
+
+}
+
 void TaskDialog::clicked(int)
 {
 

src/Gui/TaskView/TaskDialog.h

@@ -103,6 +103,8 @@ public:
 public:
     /// is called by the framework when the dialog is opened
     virtual void open();
+    /// is called by the framework when the dialog is closed
+    virtual void closed();
     /// is called by the framework if a button is clicked which has no accept or reject role
     virtual void clicked(int);
     /// is called by the framework if the dialog is accepted (Ok)

src/Gui/TaskView/TaskView.cpp

@@ -651,6 +651,7 @@ void TaskView::removeDialog(void)
     addTaskWatcher();
     
     if (remove) {
+        remove->closed();
         remove->emitDestructionSignal();
         delete remove;
     }