Disappearing Info RGB Color Values

Have you tried deleting prefs? (Restart PE, then hold down command + shift+option formac, control+alt+option for pc). Also, you might try clicking on the "more" button in the palette and then on "options" to see if you get better results with different color options.

If you are using mac os x, you can always use digital color meter from applications>utilities to check the values on any pixel anywhere on your screen. I presume there must be something equivalent in windows, but I don't know what it is.