I'm pretty new to Linux... I have Kubuntu 8.04 64-bit w/ KDE4 and am using Firefox 3.0b5.

I tried installing the mplayer-plugin and although videos play fine, when the plugin first loads, I get a gray translucent box that loads in the upper-left of the screen. Ironically, its the same size as the video window.

I can't move it, click on it... or anything. It will remain on-top of everything else. The only way to remove it is to log off and back in.

Any ideas?