I don't think it really matters Mooddswinger; like I said I use screensets and such, so I also am used to toggling views via keypress...but at the same time, buttons are good too. It's not just about easiest implementation, it's about having a solid interface for the user. All we're talking about is like a little triangle or something in one corner of the frame, not exactly majorly workflow impacting. A cohesive and coherent GUI should have a graphical representation for windows which open/close (as well as keybindings)...that's just the way I likes it. ;) oh and I am absolutely for Tree menus, definitely...