If I recall correctly (I've only ran Flash, the program, once): It has automatically merged shapes of same color into one. So to add or remove to a shape, you

If I recall correctly (I've only ran Flash, the program, once): It has automatically merged shapes of same color into one. So to add or remove to a shape, you just had to paint in the same (or a different) color. For what it's worth, I've found it super confusing.