All that being said, I find it's sometimes more beneficial to stay on the "dead" window. If one toon gets killed (usually rogues stacking abilities to 2-shot one of my shamans) it's good to change screens and drive with a live character.

If you're being bum rushed by a giant wall of enemies aoe spamming, either you're dead quickly or you manage to blast the whole wad of them quickly. In either case, I find that switching to another window, re-adjusting to the different camera angle, and establishing control just wastes valuable time, and prefer to keep casting and healing on my main window as long as my team is pointed in the right direction.