See if there is anything in the Tools/Options/AssemblyOptions - I don't have 2008, but thinking that there is a setting somewhere in the options under either assembly or performance..
Thank you John.
I can't see if any of the options you mentioned will sort the problem as I went back do a older version of the assembly and did all the work again. The problem did not came up again and I deleted the problematic assembly.
Thank you anyway and I will test this next time it happens.
It occurs because only when u apply transparent appearances to it's part file at its face/faces. to solve this Rt.Click on part/sub.ass file > Click "Open Part/sub.ass" > Goto Appearance tab in Feature manager Design Tree > Rt.Click on the transparent image > Click "Remove Appearance" > Then apply Required appearance on to it's face/part file.
Thanks and Regards
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