Trouble w/BTN nested in MC

How can I get a button to work when its nested in a MC that has an onEnterFrame with a onPress command targeted to it??

Here’s the code for my “popup” MC located on the main timeline.

popup.onEnterFrame = function(){
this.onPress = function() {
this.startDrag(false);
}
this.onRelease = function() {
this.stopDrag();
}
}

Within that same MC is a button that tells it to close. However, I run a trace command to it and nothing happens. It seems like the onPress nested in the onEnterFrame is over-riding my button on(press).

How can I work around this?