Assembly view is breaking down

Hi, I have a bug in a model that causes all parts in the assembly view to turn the default grey and lose the transparency. This makes it very difficult to edit assemblies, and the only fix I have found is to close all open assemblies and parts, and re-open. The bug occurs when I am editing a sub assembly, and often occurs when I rebuild a sub-assembly or part.

Details:

Solidworks 2010 x64 SP5.0

~200 parts, 6 sub-assemblies

I have opened the model on several different computers with the same version of SolidWorks, and had the same problem.

The bug has never occured on any other models I have made.

Any ideas on the cause of this bug would be greatly appreciated.

Thanks,

Malcolm

SolidworksAssemblies