Fix Basic Curve CV manipulation - Enable Undo:

Yes, even this has to be brought up.  As basic at it gets - when you manipulate your curves in both sketcher and style, going into CV mode somehow disables the undo, so any time you move your CVs, good luck if you made a wrong or accidental move.

Again, this is as basic as they come - a simple  undo for every move, CV or edit point, or whatever - would make functional again.