Can't Solve – Paint-doku Review

I can't seem to get past the #4 puzzle on the 15x15 group. I get stuck on the same area every time. Perhaps this is better on an iPad but it is very sensitive. It will change a square very suddenly. I like some apps that have completely different buttons for X and one for fill. Other than those things it's different and challenging.
Review by MintyFresh2.0 on Paint-doku.