Clearing a Drawing? [Mask]

Question

Hello,
So I have a project I am working on in which I would like to teach how to cash a scratch off card. I have made the scratch and made it so it will "scratch", however my masking technique seems to not be working how it should...
The idea is that the user would "scratch" the card and then hit "Next" after that it would load a new frame (Progress Bar would move) and then do what they need to on that frame, and so on.
However it would seem that Flash is keeping the users "drawing" and still allows them to draw after the first frame, which is not what I want.
Frame 1 (Before User Scratchs)                                                                                                         Frame 1 (After User Scratchs)                                                                                                   Frame 2 (After User Scratchs)
I am using this code to make the scratch effect and I am having it load extranally:
package {
    import flash.display.Sprite;
    import flash.display.MovieClip;
    import flash.events.MouseEvent;
    import flash.ui.Mouse;
    public class ScratchTicket extends MovieClip{
        var scratcherIsActive:Boolean= false;
        var stuffUnderMask:Sprite = new Sprite();
        // init class
        public function ScratchTicket():void{
            stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseIsDown);
            stage.addEventListener(MouseEvent.MOUSE_MOVE, mouseIsMoving);
            stage.addEventListener(MouseEvent.MOUSE_UP, mouseIsUp);
            // make mask           
            stuffUnderMaskClip.mask = stuffUnderMask;
            addChild(stuffUnderMask);
            makeCursor();
        // helper functions
        private function makeCursor():void{           
            trace();
        // hover effects
        private function mouseIsDown(e:MouseEvent):void{
            //Mouse.hide();
            Mouse.cursor="hand";
            scratcherIsActive = true;
        private function mouseIsUp(e:MouseEvent):void{
            //Mouse.show();
            Mouse.cursor="arrow";
            scratcherIsActive = false;
        private function mouseIsMoving(e:MouseEvent):void{
            if(scratcherIsActive){
                stuffUnderMask.graphics.beginFill(0x000000);
                stuffUnderMask.graphics.drawEllipse(mouseX, mouseY,60, 60);
                stuffUnderMask.graphics.endFill();
    }// class
}// package
I would load this script locally, however I am not sure were to place it, or if it would even help.
Thank you!

Answer 1

Are you handling the situation that the user may leave the flash area altogether? This is often a problem. Even if it doesn't solve your issue, I see no mention of MOUSE_LEAVE in your events.
I would change the event your mouseIsUp(e:MouseEvent):void function listens for to a generic event. So private function mouseIsUp(e:Event):void. Then you can do this:
stage.addEventListener(Event.MOUSE_LEAVE, mouseIsUp);
That will make sure that if the user leaves the flash area the mouse will have a chance to run mouseIsUp().
When your user is done scratching don't forget to dispose of the surface you're drawing on with the graphics.clear(); method (e.g. stuffUnderMask.graphics.clear();) as well as removing any objects made to draw on.