Localized undo for fill tool

Wanted to share this idea I just had: I could make “right click with the flood tool selected” be “turn the cell into the last color this cell was”.

I think it’s unacceptable to lose the ability to just straight-up-erase a cell… but this sort-of-localized-undo is often what I want when I right-click.

I feel like there’s something good here, but not what a good choice of specifics would be.