I spend a great deal of time stepping through stuctures residue-by-residue (space bar) and rotating the molecule to and fro as a check up. Basically I have the mouse button held down almost constantly. I wondered if it would be simple to have a key binding to toggle in/out of a special rotate only mode, analogous to the mouse button being taped down while in that mode. This would also make apple's little track pad pretty handy for rotating which it currently isn't since it's hard to depress the whole pad (the click) and keep it down while rotating. I've tried using the "i" = constant rotate but you end up wanting to rotate different ways at each new residue, and yes, I've even briefly experimented with a very literal "mouse button taped down" hardware implementation (generous term for it), but I'd like a faster way to get in and out of the mode (for when you need to interact with accept/decline windows, click on a menu, or go to other applications, of course).