I noticed that if an app written in API V2 adds objects to the canvas, the “undo” functionality doesn’t remove those items. A good example of this is the “Puzzle Designer”. After importing the puzzle pieces, Edit > “Undo Import from App” or “ctrl/cmd z” doesn’t remove the puzzle pieces that were added, in fact it doesn’t do anything other remove that item from the history.
We actually already have a fix for that in the pipeline. Stay tuned.
Thanks for the bug report! It should be fixed now.