Steps to reproduce:

1. Load two images (e.g. E130-Daten/MITK-Tutorial-Demo-Data/Registration/moving-affine and fixed)
2. Open Rigid Registration Plugin
3. Select two images
4. Choose a registration method
5. Click load preset
6. Choose registration method "== select a registration configuration =="
7. Click load preset

--> workbench crashes

Possible solution: Disable button when "== select...==" is selected.