Undo / Redo needed

[ddwek]

Hi everyone, I was doing my diagrams on Oregano but fix some mistakes is getting a little tricky. This is because there's no undo and redo commands in neither menu bar nor tool bar.

I think that I can write the code necessary to work it out and, therefore, improve the look & feel of this program. Obviously, I need your authorization to contribute with my new branch, that usually I used to call "contrib". Thank you very much and best regards.

[drahnr]

Hey, usually changes are introduced by creating a fork and creating a PR based on that, there is pretty good howto for github https://docs.github.com/en/github/collaborating-with-pull-requests which does not require you to get access to this repository.

I'd be happy to include such a change!