I took some screenshots to demonstrate my problem.
I start mapping with this:

I make a hollowed room, all fine and dandy, until I zoom in the 3d window a bit.

The view gets all skewed, nasty, and unusable.
If I zoom back out, it's fixed until I zoom back in again.
Can anybody help me please?
(In the first pic, you see that I'm addicted to World of Warcraft.
