Max viewports showing two-sided faces?

[Blocked Image: http://beancitynights.org/gamedev/2side.jpg]

The cylinder on the left is unmodified, the one on the right I converted to editable poly and deleted the top face. Notice how faces that don't exist are showing up as solid?

This happens with all materials and I seriously cannot figure out why. This is a fresh install of max and it's never happened before.

suggestions?

edit: force 2-sided is definitely off in the viewport options

Quote from ctswin

customize > preferences > viewports then backface cull on object creation?

cool, that worked... unfortunately it doesn't affect models i've already made

thanks guy