I'd like to write a jiffy that binds the up and down arrow keys to move up/down the list in the object/selection pane. I'd like (for example) pressing the down arrow to equate to clicking the currently active object (thus hiding its representation) and clicking the next object down (thus showing it). That way, none of the various cartoon/stick/spheres are lost, but the current object disappears and the next one appears. What is the pymol command for choosing/un-choosing [sic] something in the right-hand panel?