whole desktop is dimmed when vlc video is focused

[zaffi]

when i play a movie, my desktop is dimmed after 2-3 seconds.
the brightness is restored when i take to focus out of VLC video window.

Even if the focus moves to VLC's own dialogs, (e.g. preferences), the brightness returns to the desktop.
when i click VLC's main window, the screen is dimmed again.

this drives me nuts.
usually it does happen. sometimes it doesn't happen.
i can't figure out when or why it happens.

i'm on Windows XP SP3, VLC 1.1.4

[VLC_help]

So VLC stays on screen but everything else goes dark?

[zaffi]

everything goes darker.

it's more obvious when not in full screen:
when i bring VLC to focus, all the screen becomes gradually (in 2-3 seconds) darker: background windows, vlc, task-bar..

[VLC_help]

Does it help if you disable VLC's screensaver option?