System Preferences - Displays - Confirm resolution change?

I'm trying to change resolutions for both my 23" Apple Cinema Display (ADC) and a Panasonic HD projector (hooked up via a DVI-to-VGA adapter) but am having some problems. I used DisplayConfigX to create some compatible resolutions for the projector and most of them work fine. However, it seems that there are also some new resolutions for my Apple Cinema Display that absolutely do not work. If I accidentally select one of those resolutions, the monitor goes black and just flashes the power button. The only way to get it working again is a hard restart in to Safe Mode and then I can reset the resolution.

My question: How can I get the display to return to the previous resolution if the screen goes black after changing to a new one? It used to be that if you didn't confirm the new resolution, the display would automatically return to the previous resolution after about 15 seconds. What happened to that "feature?" Was that in OS 9 or is there a way to invoke that confirmation dialog in OS X?

Any help is greatly appreciated!

Brent