Overruled mouse events because of movieclip on top

Hello all,

Currently I’m trying to learn AS3/CS4. And today I discovered a problem I never had in AS2.
I have a button which is below a movieclip. This movieclip has no buttons inside or something like that. So the roll over from the button shouldn’t be overruled I thought. This is not true.

The roll over, out and click doesn’t work on the button anymore.

How can I get the button to work again (without removing the movieclip of course).
I uploaded a file so you don’t have to make it yourself.

Thanks in advance,
Harm