Yeah, the bounds checking for clicks isnt something that fit so isnt really there :)
Since I also wanted it to be more feature-full than my original submission, I did spend some time this week doing some compression/cleaning and adding the features I really wanted: automatic 0-filling and right-click flagging within the limit (I never wanted to get rid of that or else I could easily just do the whole thing with timer and stuff). And so how, it all fits in exactly 500 characters:
