Service pack 2 bug?

Hi i have just updated to service pack 2 from 1 on vista 32HP8710w nvidia fx1600m
Before update if i change a parts transparency the part becameopaque.Now it is not see through but it acts as a transparent partwhen i click on the transparent part it selects the Part behind it.

How do i fix this
Is it a setting

Thanx
Neels AudieSolidworksEdrawings