There IS a little U-on-its side arrow thing next to the swatches in Photoshop which does that. It's close to that other thing that switches the colors to black and white. I don't have Ps at work, but I'll try to remember to send a screenshot from home. Er, if I can find your email. (My email is dd 'hyphen' b 'at' dd 'hyphen' b 'dot' net, if you see what I mean.)
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I don't find the help all that useful either.