Calculate selected records on feature class with joined table

When I use the Field Calculator on selected records in a feature class that has a joined table it calculates the entire table as if there were no selection set applied. The Field Calculator works as expected on the feature class without the joined table, i.e. it only calculates selected features. Is this a bug? Is there a way to have it only calculate the selected records on when a table is joined?

I haven't tested it on all formats but this is occuring in a file geodatabase feature class with a stand alone table joined. (Arcgis 10.0, Windows XP).

thanks.