Make it where you can use keyboard shortcuts such as Ctrl + Z (Undo) and Ctrl + Y (Redo) in any text field in the game; also make these shortcuts configurable. I didn't see any suggestion when searching, so please correct me if I'm wrong.
EDIT: I forgot about Ctrl + BACKSPACE, but would be cool for the same functionality to be used with Ctrl + Z; however, I don't know about any functionality in the game for redoing text. Lookup "keyboard undo and redo shortcuts" on Google if you're unsure as to what I'm talking about.
(I'm primarily talking about chat though)
it undos certain characters and redos them