What is that?
AS3 has a new feature, which is called bubbling. As an example check the movie below and click on the menu buttons. In the right menu you see the negative and positve effect of bubbling. When you press the Menubutton, the Linkbutton will appear. When you rollover the Linkbutton or press it the Menubutton will also react, because the Linkbutton is a child of the Menubutton. On the other hand the Linkbutton will disappear after being pressed, which we want. In the menu on the left side we are preventing bubbling. Now only the Linkbutton changes after rollover, however when we press the button it will not disappear. If we now mix both effects, we can easily choose only those effects, which we want.