Since I bought my iMac last year, I have a white pixel on the left of my screen. I'm ok with that, one pixel is not much and I know about dead pixels policies.

My problem is about understanding this "dead" pixel.

But this pixel has a strange behavior. At first, it seems to be always white, but it is actually working ok under certain conditions:

• the mouse pointer
• a contextual menu
• Dock icons
• a QuickLooks video played in fullscreen
• other spaces than "1"

The "QuickLooks fullscreen video" and "other spaces" are the one that disturb me the most. In these modes, my pixel is working fine, so it must be a software problem since my pixel is working correctly in those modes.

Any ideas?