Fix invalid state on restore

- Overlayed dock areas should not be added to the d->DockArea list
- As they are not treated like normal dock areas

src/DockContainerWidget.cpp

@@ -1115,7 +1115,6 @@ bool DockContainerWidgetPrivate::restoreOverlayDockArea(CDockingStateReader& s,
 	else
 	{
 		DockArea->setProperty("currentDockWidget", CurrentDockWidget);
-		appendDockAreas({DockArea});
 	}
 
 	return true;