One object with a mouse event over another

I know I’ve come across this before, but I can’t seem to find anything on it.

I’ve got a movie clip with an onRollOver event. As a child of that movie clip I have a button.

Because of the onRollOver event on the parent clip, the onPress event for the button does not fire correctly.

Like I said, I’m pretty sure I’ve come across this before, probably even had to work around it. Anyone know of a workaround, or a fix?