It sounds as though you just need to add a stopDrag command on a release event...
The second startDrag parameter is what locks the object to the mouse if set to true....
target:Object - The target path of the movie clip to drag.
lock:Boolean [optional] - A Boolean value specifying whether the draggable movie clip is locked to the center of the mouse position (true ) or locked to the point where the user first clicked the movie clip (false ).
left,top,right,bottom:Number [optional] - Values relative to the coordinates of the movie clip's parent that specify a constraint rectangle for the movie clip.
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