This patch causes the changed area to become selected during undo/redo operations.
This will not reset the selection to what it was before the editing operation, but it gives very good
user feedback as to what changed and in many cases does restore the selection. I'm working on
a patch for that but due to a few outstanding bugs it may be a while before I submit it.
I would appreciate some people giving it a try and giving some feedback as to how good/terrible
this would be. This is how many modern word processors work.