Shift-click accumulates selection. (I know shift-click accumulates selection! I know that!)

Prior to ArchiCAD 8.0, the shift-click functionality could be modified by activating Caps Lock. With Caps Lock active, shift-clicking on unselected elements would select the clicked-on element and deselect all others. This was invaluable in getting a particular element out of a pile. But it made newbies cry so they got rid of it. (I was typing, notes, with all caps, an-and, then I went to uh, uh, uh, select, something, an-and, caps lock was still on, an-and, uh, uh, uh, the selection didn't accumulate, an-and, I had to move my left hand a quarter inch, to, to, to, turn caps lock off!!! MMMWAAAAAHHHHH!!!!)

In AC9, they have restored the functionality, while throwing the newbies a bone by not using the caps lock key to do it.

If you hold down Command along with shift, the selection will rotate through the elements at that point. With a particular tool active, it will rotate through the elements of that type. Don't forget Quick Select!