How come my button only works if I press it in a different place each time?

programming flash
1

Hi there, I can’t figure this one out. I have a button called ‘Preview’ that works fine when pressed initially. When I press it again, having selected a different item in a combo box that is in the movie, it only works if I move my mouse and press a different part each time.
I’ve defined the hitArea and I can’t think of anything else.

I have tried using a button component and this works fine.
Thanks!
Schm