It's not consistent... sometimes the stripe is gone, sometimes the stripe is blue, etc... And the reflective Dock draws just fine. Somehow, I still prefer the ugly stripe to the 3D reflective Dock.
Most recently, I used Candybar. But it did this even when I used the terminal command to change it.
It's not just the Dock either... here's a screenshot from Front Row:
Suspecting that there may be something wrong with my Leopard disc, I used it to install Leopard onto another computer, and it draws the 2D Dock just fine. Must be a hardware problem then, huh? The Mac with this problem is a 12" PowerBook G4/867 (a Leopard supported machine, according to Apple). I never had any strange drawing problems like this with Tiger.
Edit: if it were solely a hardware problem, screenshots would appear normal, right?
Most of the aforementioned drawing problems seem to go away when I use Quartz Debug (included with Leopard Developers Tools) to turn off Quartz Extreme. Will I encounter any problems by leaving Quartz Extreme off?