I have a stack with all the actions the user does with my editor, and pressing control + Z undoes the last change. You can also press control + Y to redo thr last undone change. It was a cool software engineering challenge
Spine?
Really cool banner you have in there! Welcome to Reborn and may the metal be with you! And it's also great to have another programmer on board.
Btw, maybe I'm blind but I can't find Metallica nor Tobias Samett's Avantasia