title: Why doesn't setMask work is this example after it worked once
body: <p>I'm trying to use setMask to create 3 "windows" of masked movieClips in AS2 (CS3).</p>
  
  <p>The main window is masked fine.</p>
  
  <p>After clicking a button, I'm creating two additional windows, but the refuse to be masked No error, it's just that the mask is not applied, and the mask rectangle is still visible.</p>
  
  <p>All 3 windows are masked using the same function, with different MC parameter.</p>
  
  <p>I have nested MCs, but basically, the main window is masked as:</p>
  
  <pre><code>_level0.GUI.OBJ.mainWinMC.mainWindowMC.mainWindow.setMask(_level0.GUI.OBJ.mainWinMC.mainWindowMC.mainWindow_PlanMask);
  </code></pre>
  
  <p>where <code>mainWindow_PlanMask</code> contains an MC with a red rectangle. (Note: I'm using MovieClip variables and I posted here their movieclip traced path.
  This works fine.</p>
  
  <p>After pressing a button, I'm setting two more masks:</p>
  
  <pre><code>_level0.GUI.OBJ.mainWinMC.side0MC.side0.setMask(_level0.GUI.OBJ.mainWinMC.side0MC.side0_PlanMask);
  
  _level0.GUI.OBJ.mainWinMC.side1MC.side1.setMask(_level0.GUI.OBJ.mainWinMC.side1MC.side1_PlanMask);
  </code></pre>
  
  <p><code>side0_PlanMask and side1_PlanMask</code> contain rectangles too.
  But in these cases, the red rectangle is kept visible and the mask is not applied.
  I have no idea why. Any help will be appreciated.</p>
  
  <p>[Edit]
  applying cacheAsBitmap all MCs from both mask and masked MCs to the _root caused the first mask operation not to work as well.</p>