# Masking a movieclip with masks in it causes a lot of problems

**URL:** https://forum.kirupa.com/t/masking-a-movieclip-with-masks-in-it-causes-a-lot-of-problems/270515
**Category:** Uncategorized
**Created:** [September 10, 2008, 5:29pm UTC](https://forum.kirupa.com/t/masking-a-movieclip-with-masks-in-it-causes-a-lot-of-problems/270515 "2008-09-10T17:29:18Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![praxiz](https://avatars.discourse-cdn.com/v4/letter/p/779978/32.png) [@praxiz](https://forum.kirupa.com/u/praxiz)
#### Post date: [September 10, 2008, 5:29pm UTC](https://forum.kirupa.com/t/masking-a-movieclip-with-masks-in-it-causes-a-lot-of-problems/270515/1 "2008-09-10T17:29:18Z")

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Hi there. I’ll try to make this brief.

I have a movieclip (“Projects”). Inside there’s a Movieclip (“Thumbs”). In this mc I have a script which dynamically loads a bunch of images and texts. Because the images are varied in size I simply set all images to a certain width and apply a mask to them thats’ the same width and height as the width of the image, thereby causing all “standing” images to be cut to the same height. Looks a whole lot better and I can keep the text (which is under the images) at the same Y position.

(The thumbs are in three columns)

This all works great. BUT. Now I want to add a mask to “Thumbs” so that I can add a scroll to the whole thing. The scrolling works but the images in “Thumbs” seems to be having trouble. Some of the images simply won’t show up. The first thumb I load shows up fine, but the rest, not so much. And even weirder, if i scroll down, one of the images seems to appear and reappear, depending on how far down I scroll. This is the 4th thumb, the one directly under the 1st thumb, which works fine.

Edit: I should probably also mention that my computer crashed once after I had played the swfmovie for a while in Flash CS3. It usually doesn’t do that.

Can anyone figure out why this is?

I don’t think I can share this FLA with you since it’s a work product and I’d probably get fired if I did 🙂 but here is the code for the thumb masking.

```php
var thumbMask:Sprite = new Sprite;
thumbMask.graphics.beginFill(0xFF0000);
thumbMask.graphics.drawRect(0, 0, child.width, child.width);
thumbMask.x=changex;
thumbMask.y=changey;
thumbMask.graphics.endFill();
thumbMask.cacheAsBitmap;
addChild(thumbMask);    
child.mask=thumbMask;    

```

I draw the scroller mask manually and name it “mask”, and the rest is basically this thing:  
[http://ffiles.com/flash/user\_interface/fully\_customizable\_scrollbar\_class\_v\_2\_1742.html](http://ffiles.com/flash/user_interface/fully_customizable_scrollbar_class_v_2_1742.html)

I really appreciate any helpful suggestions you might have.