FLASH: Why won't my white circle show in movie-preview?

[Michael Galvin]

I created a small white (ie., no line, white colour inside) which I'm scaling to take over the whole stage along the timeline.  As I play through the animation on the stage, everything works fine, but when I use ctrl-enter to preview the movie, nothing happens.  The layer is played, but the circle doesn't cover over everything on the stage as it does with the "simple play".  If I tint the circle any other colour except white, everything works fine, so why doesn't a white circle (regardless of tint, brightness, alpha, or special settings) overwrite objects?

 

http://homepage.tinet.ie/~mpgalvin/humour.html
Because I'm worth it