Just started a new project. After tagging I normally put all items of a same kind on a separate track and pre colourgrade them so I have the same settings on all items before I assemble them to a track.
After importing and tagging I have put a row of images on a track and decided to undo this by ctrl+z
Nothing moves. Only forced closing by taskmanager ends it.
This leads to the attached screenshot situation. (Vegas and Taskmanager)

Reopening the project starts with last saved situation, pictures in place but not crashing.

I have set instant safe. Maybe that is a problem?