Hi If I have my external monitor (22" Samsung LCD) plugged in but turned off, then the mouse pointer and/or keyboard entry (back on the main iMac desktop) pauses for about half a second, just about every second or so for the duration the external monitor remains switched off. If I unplug or switch on the external monitor, then mouse and keyboard response is immediately restored to normal. (Other processing appears to be unaffected.) I've had this problem for well over a year now, stretching back to OS X Snow Leopard, at least. I've been waiting patiently (mostly) for a software update to fix it. But it hasn't come. (Currently running the latest rendition of Lion 10.7.4 [updated].) So I thought I'd ask here, to see if others might have noticed the same glitch / bug?