Fix Carla breaking GUI on Wayland #7582 (#7966)

src/gui/instrument/InstrumentTrackWindow.cpp

@@ -294,10 +294,10 @@ InstrumentTrackWindow::InstrumentTrackWindow( InstrumentTrackView * _itv ) :
 	vlayout->addWidget( m_pianoView );
 	setModel( _itv->model() );
 
-	updateInstrumentView();
-
 	QMdiSubWindow* subWin = getGUI()->mainWindow()->addWindowedWidget( this );
 
+	updateInstrumentView();
+
 	// The previous call should have given us a sub window parent. Therefore
 	// we can reuse this method.
 	updateSubWindow();