This is happening between two almost identical iMacs (only difference is one is a 2.4 GHz and the other one a 2.66 GHz) running 10.5.4 with all security updates, same keyboard type, same keyboard input type, etc. The usual keyboard command for "Move focus to next window on active application" is the "cmd" + "<" keyboard combinations. On the new machine the keyboard combination for the same command is "cmd" + "`" but it just doesn't work. Is there any way I can change this keyboard combination so that it will match between all my Mac's? PD - Maybe this key combination is in used by another system function, but I cannot find what it is. Update: I just realized that my new MacBook has the same keyboard combination (second one) that also does not work (by not working I mean that when pressing that keyboard combination absolutely nothing happens).