In NX5 you could 'deselect all' in the 'referance sets' dialogue to clear everything before selecting teh geometry you wanted. The only way I have been able to do this in 7.5 is to turn all layers on and unblank all to do a mass deselect. This is obviously a pain, especially if the file has...
I have just organised updating from NX5 to NX7.5 for our 9 seats of UG within the company. Most of the changes are logical and easy to understand. However, I missed whilst testing it that assembly mating conditions has changed to constraints (partly becuase it happened in an earlier release...