I discovered something by accident this morning.  Maybe everyone else knows about it, but it was new to me.  Hitting the C key on my keyboard (Just C, not Shift+C, which collapses the regular tree) will collapse the tree in the graphics area.  If it's already collapsed, the same command will expand it.

It shows up in the Keyboard shortcuts under Customize, so apparently it's a default setting; I just never noticed it.  Anyway, I thought it might be helpful if there's anyone else out that didn't know about it.