Steps to reproduce crash:
- load an image (I used Pic3d.nrrd)
- open segmentation view
- create a segmentation (don't use add, regiongrowing, etc.)
- close segmentation view
- select segmentation in datamanager
- open segmentation view
- choose an editing tool (eg. add)
- try to paint in the picture (here does only the crosshair move)
- select your picture, then again the segmentation
- choose again an editing tool and paint in the picture
- close segmentation view
- it crashes now by reopening the view, while the segmentation in the datamanager is selected