face selection broken in 2.5?

I’m trying to select and hide faces in Weight Painting mode and I can’t seem to make it happen. I go into face selection mode (no F shortcut in 2.5…you just click the icon) and I can select faces. However…when i try to hide them, it hides the bone I’m editing.

Also, selecting faces (or not) seems to make no difference on what faces get painted.