Mouse not centered

Hello,

Below is my code to move a clip called myCLip
this.monClip.addEventListener ("pressmove", fct.bind (this));
function fct (evt) {
var p = this.globalToLocal (evt.stageX, evt.stageY);
this.monClip.x = p.x;
this.monClip.y = p.y;
}

How can I prevent the mouse cursor from being positioned at the center of the myClip object?
Thank you for your reply.