Photoshop CS4 - New file shows triangles of uneditable areas.

Recently got PS CS4 (looking good). However, when I create a new image, be it white BG, transparent, etc. I'm greeted with a few triangles of what appears to be transparency. I'm unable to draw into these triangles, and that is getting on my nerves. I'm sure there's some professional reason for them, but I'm not a professional and I would like to get rid of them. I don't remember this happening with CS3.

Image:

Anyone know the reason for this monstrosity and how I can do rid of it?

re: Photoshop CS4 - New file shows triangles of uneditable areas.

Turns out, it's to do with an issue on my Graphics card. The fix is simple:

Edit -> Preferences -> Performance -> Deselect 'Enable OpenGL Drawing'

I can get to work now :D