Oh, I have a few questions about effects too!
Does erase do nothing else than changes the object it's applied black? Isn't it basically the same as applying a black colour filter?
Back then, there was discussion about "cookie cutter" effect, or something like that. Is that effect implemented? The description of "Mask" looks like it, but it just reverses the alpha channel.
Are the "combine" effects supposed to look this messy?
http://student.sipoonlukio.com/~kontiopyry/misc/combine_additive.png
What do they actually do?
Does Glow have any other usage than using it after blur?
What kind of blends are Overlay and Screen?