Undo button?

[b321gonzo]

An undo button would be really helpful.
For instance if I'm on step 3 and am using the draw function and mark or change something I didn't want to, instead of trying to erase everything and start over and instead of erasing single lines (might be drawing on a drawing) and instead of recoloring things, and undo button would be nice.
Another instance would be if I'm on step 3 for available pieces and I have my own pieces inputted, then I switch to all tile colors which does infinite count, if I want to switch back to what I own it would be easier to click undo rather than clearing all pieces and selecting the sets to mix in (which I have multiple small sets so it's a pain).

[baconlord6]

I would like this.