Today I was working on some code, nothing particularly different than any other day. I did something I have done thousands of times before, made some changes, and then needed to get previous code back. This was quickly done with undo several times, copy to clip board, redo several more and then paste. Then it hit me, why don't we have an undo within selected text? We have a search and replace within selection. Undo within selection complements the search and replace really well, and further, allows for quicker retrieval of code several edits ago. Particularly when the change was a single iteration ago in a particular location… In a sense spatial undo versus temporal undo.
Hopefully this will make it into Visual Studio some day, either as a power tool or third party plug-in.