Toon Boom was driving me up the wall today. I only was able to get 3 drawings lined and colored, still have to do the transitions and Hiro's response.
Flash sometimes had an issue when drawing a figure that, even though it was closed, a microscopic gap existed which prevented you from filling it.
Toon Boom's gaps by comparison are much easier to see... but they're also WAY more frequent. It was giving me a headache to color this, else i would've gotten further today.