To reproduce:
- Start MITK workbench with overlaymanager-plugin enabled
- Open the overlay-plugin and close it
- Change the focus by clicking e.g. into the StdMultiWidgetEditor
- Workbench crashes in itkCommand.h, coming from RenderingManager::SetRenderWindowFocus
My guess is that the itkCommand is not removed from the rendering manager as an obvserver, if the overlay-plugin view is destroyed.