The undo function does not work any longer…
There are some usually rare occasions that break undo. But in general it should work.
You can re-open the font to make it work again.
If you can reproducibly break the undo, please tell me the steps and I’ll try to fix it.
There is a plugin that syncs metics keys. That will break undo for sure.
Wow, yes, it was the ‘sync metrics keys’ plugin that caused it! I removed the plugin and the undo function works again! Thanks Georg!!!