Here's a short video I just uploaded which illustrates my problem. Random parts just disappear when moving the cursor over them in an assembly.
I'm using SW 2012 SP 4.0 on Windows 7, being emulated with Parallels on a Mac Pro (32GB RAM, 2 x 2.93 GHz 6 core Intel).
From what I'm seeing, it's a graphics card issue. Have you done any updates recently? You might look at trying different graphics drivers and see if that changes things.
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