Fixed issue #597 - Crashes when the floating widget moves to the dock manager and then tries to drag it back

src/DockContainerWidget.cpp

@@ -1643,6 +1643,15 @@ emitAndExit:
 }
 
 
+//============================================================================
+QList<QPointer<CDockAreaWidget>> CDockContainerWidget::removeAllDockAreas()
+{
+	auto Result = d->DockAreas;
+	d->DockAreas.clear();
+	return Result;
+}
+
+
 //============================================================================
 CDockAreaWidget* CDockContainerWidget::dockAreaAt(const QPoint& GlobalPos) const
 {
@@ -1756,7 +1765,7 @@ void CDockContainerWidget::dropFloatingWidget(CFloatingDockContainer* FloatingWi
 	if (Dropped)
 	{ 
 		// Fix https://github.com/githubuser0xFFFF/Qt-Advanced-Docking-System/issues/351
-		FloatingWidget->hideAndDeleteLater();
+		FloatingWidget->finishDropOperation();
 
 		// If we dropped a floating widget with only one single dock widget, then we
 		// drop a top level widget that changes from floating to docked now