Recently VLC has been having issues displaying video in fullscreen mode. AFAIK, nothing has changed with the video card drivers and it's certainly the same version of VLC. (/me shakes a fist at the repository maintainers)

This has worked without issue in the past. In fact, I've had as many as 6 instances of VLC running, each playing a video. One was always fullscreen on my second monitor, while the others were tiled on my primary monitor. I was able to toggle any of the other 5 into fullscreen mode and the video displayed without issue.

Lately, I've been having trouble running 2 instances in fullscreen mode. (Sometimes, even a single instance will not display the video in fullscreen.) VLC will continue to play the video, but in fullscreen mode I see nothing but a black screen. Sometimes, the video will display if I maximize the VLC window. Other times, I have to settle for a smaller sized window.

I don't know if this is pertinent, but sometimes changing the min/max state of a Firefox window (Minefield, specifically) seemed to allow the troublesome instance to display the video in fullscreen mode. However, that did not prove to be a consistent workaround. Sometimes, it seemed that closing a Firefox window did the trick, though that isn't consistently successful either. (I futzed with Firefox, because with the crazy number of windows and tabs that I normally have open, it regularly hogs about 1 GB of RAM.)

Another bit of funkiness that comes to mind is the fact that my secondary monitor is considered the primary on boot-up. I use xrandr to designate the real 1st monitor as primary after boot-up, as suggested by someone in a question I asked on the Unix & Linux SE site.

Specs:
Ubuntu 10.10 w/ Gnome and Compiz
8GB RAM
AMD Phenom II 965 Black Edition
Asus M4A79 Deluxe mobo
XFX ATI Radeon HD 5750 w/ 1GB RAM

VLC is configured to use the hardware overlay for video (as per the default setting)

Does anyone have an idea what may cause this issue or how I may go about troubleshooting it?

Update:

Right now I have 2 instances of VLC playing, each in fullscreen mode on a separate monitor. This is what I see: