Feature Request: Undo for TextDiagrams

[As I somehow cannot find a way to create ideas, doing it as a discussion seems the most appropriate path remaining.]

Current situation:
If by random or mistake I overwrite or delete something in a text diagram it is gone forever if it was not included in the last saving (e.g. I try to copy something, mark the section, press randomly only "c" instead of CRTL+c and the marked section is replaced by "c". No chance to get back what I wanted to copy... )
The only thing I can do is a "reload/revert" - to speak in ordinary text editor terms: I can do an undo, that brings me back to the last saved state of the text diagram content.
Even with an active ChangeControl there is only the Information available THAT I changed the text, not WHAT I changed in the text. A redo that would allow me playing around to find out about this is not available either.

Desired behavior:
As with all other changes I would like to have an undo within the text diagram / the RTF editor. I would expect an undo behavior as common in ordinary text editors.
To keep it simple: Adding a "local "undo/redo for the text diagram's text editor (just for the phase of editing between two "save" actions) would already be very helpful.
An additional redo from saved state to saved state would be the next level.

By the way: Enhancing the capabilities of the integrated (RTF) text editor would be very nice anyway. Being forced to copy the text to WORD (as RTF editor), edit there and copy back to be able to use more of the RTF features than the very limited set available in Modeler 8.3, is not very satisfying.
What I find even worse is the limitation that working hyperlinks are not supported (means: hyperlinks that open the browser (or whatever protocol-associated tool) when they get clicked) - see related post [Feature Request: Active Hyperlinks].