Thanks for your help!

To recreate the crash i'm experiencing, add a node and 10 subnodes. Select the last subnode and press the delete button until the program segfaults.

I tried to use ModelTest but it doesn't give me any hints unfortunately. Honestly though, i had to modify the test first because it didn't like how the text for each item was dependent on its index. The test assumes an object will have the same text before and after its moved, which is not the case in my example. But after that slight modification, ModelTest doesn't say anything, despite the crash i'm seeing. But the fact that i had to modify ModelTest was what prompted me to ask my question here in the first place, perhaps moving items around in the model the way i am is the reason for my problems, and should be done via say, a QSortFilterProxyModel instead.