Need help with clicking a movieclip

1

I am building a game that has a power bar and an angle meter. Both, the user sets.
The power bar works fine (so does the angle meter) except for the fact that it moves whereever the mouse is clicked.

with this code:

onClipEvent (load) {
     _x = 500;
     _y = 250;
     scrollerClicked = false;
 }
 onClipEvent (mouseDown) {
     scrollerClicked = true;
 }
 onClipEvent (mouseUp) {
     scrollerClicked = false;
 }
 onClipEvent (enterFrame) {
     if (scrollerClicked) {
         endY = _root._ymouse;
         _y += endY-_y;
         if (_y < 160) {
             _y = 160;
         } else if (_y > 340) {
             _y = 340;
         }
     }
 }

Is there a way to make the scrollerClicked variable only true when the actual movieclip is clicked, not anywhere on the stage?