I have difficult time to find exact recipy but it happens couple times a day when working intensely with beamer:
Inserting new frame, calling undo. At this moment lyx freezes with 100% CPU consumption. I had working example and while striping complexity to get MWE, I lost it... In that moment the reproducible recipy seemed to be: 1. Being withing nested environment inside frame 2. Insert new frame 3. calling undo 4. inserting new outer frame 5. calling undo 6. freeze Hopefully will get some file where it works some day, but perhaps this rings a bell to someone. E.g. missing some undo group call for inserting frames? Pavel
