Don't know if this is a bug or not, but it's something that I've only just spotted after years of using AS (I'm on AS 10 on the Mac)
Trying to create a boolean compound shape by intersecting two simple shapes and filling the gap I want to be the compound shape.
As the manual's example describes, it works fine for two circles, but if I want to fill the gap in a circle after a triangle's intersected it, it also fills the outer bit of the triangle. Is this the expected behaviour?

Apologies if I'm being stupid and there's an easy fix.
It only seems to happen when you intersect with a triangle. I can work around it by using the point of a star as the triangular shape and then the rest of the star doesn't fill with colour..