In ActionsScript 3.0, to get the height of the stage you’d use ’stage.stageHeight.’ In my case, I was working with a 600 x 400 Flash file with movieclips that needed to be vertically centered. After publishing, the vertically centered elements were not centered properly. This led me to re-examine my code and math quite heavily. Nothing appeared to be in error. Tracing out ’stage.stageHeight’ reported back a height of 300. This was obviously wrong since my project was 400 pixels tall. Resizing the stage to 300 made my trace report back a height of 200. I reset my stage to 400 tall and thought about the problem. So everything was off vertically by 100 pixels. Odd.

On a whim I did a test movie.  I then, ever-so-slightly, resized the preview window and hit the ‘test movie’ hot key again. A had adjusted the window only a few pixels. Instead of reporting back, say, 303 pixels it was now reporting 403 pixels. Ah-hah! Now I had an idea what was wrong: Flash was being a pain in the butt. Continuing my whim, I turned off the bandwidth profiler I often leave open and recompiled . . . 400! Stupid Flash! The bandwidth profiler seems to have an issue eating up vertical pixels.  Bad Flash.  Very, very bad.