1. Start Krita 2. Create a new file 3. Add "Transparency Mask" to the top Layer by clicking context menu in layer dock 4. Select "Transparency Mask 1" by left click "Transparency Mask 1" in layer dock 5. Hit "Ctrl + g" to create quick group of "Transparency Mask 1" 6. Crash!
Created attachment 102585 [details] (GDB Report) Yes, it happens to me too (Krita 3.0.94 - Ubuntu 14.04). GDB report in attachment and confirming.
Git commit 0cfe13b5451ead005bb5d325a051939f1de0adf6 by Boudewijn Rempt. Committed on 07/12/2016 at 12:12. Pushed by rempt into branch 'krita/3.1'. M +3 -3 krita/krita.action https://commits.kde.org/krita/0cfe13b5451ead005bb5d325a051939f1de0adf6
Git commit 661b851209339a7fd0eaa9e6ee86b372a8e6c346 by Boudewijn Rempt. Committed on 07/12/2016 at 12:12. Pushed by rempt into branch 'rempt/impex-refactoring'. M +3 -3 krita/krita.action https://commits.kde.org/krita/661b851209339a7fd0eaa9e6ee86b372a8e6c346