Possibly relevant other Undo issues:
https://forum.vassalengine.org/t/undo-problem-captured-in-log-file/7622/1
vassalengine.org/tracker/sho … i?id=12951
https://forum.vassalengine.org/t/test-builds-for-3-3-0/10056/91
https://forum.vassalengine.org/t/test-builds-for-3-3-0/10056/170
https://forum.vassalengine.org/t/test-builds-for-3-3-0/10056/195
Several of these links are for a problem which was reported against some earlier 3.3.0 test builds C&C which had a fix for Bug 12538 that had some unintended consequences for Undo. (I still don’t grasp why these changes cause a problem, as they look right to me.)