AutoCAD 2010/2011/2012 DWG Format

[#1]

I have 1 file that I'm working in, which is a complex 3d object, and when I draw a crossing window (for selection) the window appears to be filled in white.  Can anyone tell me what's going on?  If I open any of my previous files or start a new 3d file, the crossing window displays correctly.  Thanks.

[#2]

Well, I just sort of answered my own question.  I had recently turned my hardware acceleration off because my interface had become choppy.  I've done this in the past and didn't have this same issue.  I'm still interested in hearing what the members have to say about this.