Undo does not work

[JohnKlenk]

1.) In the sample browser (Sample 8 - Web Browser), type something in the address field, or in an input field such as the search box on https://www.google.com/.
2.) Press Ctrl-z.

Expected: Undo occurs.
Actual: Nothing.

This was included in #254, which was closed apparently because the cut/copy/paste part was in the #178 "megathread". But I think that was a mistake because undo is still broken.

I'm using the latest SDK with AppCore.dll dated 2022-02-17.