I have run into a minor issue where the selected color value changes after I have entered a hex value into the picker.
For instance, if I enter "cccccc" and then click "OK" the value gets changed to "cdcdcd". Also, if I pull up the color picker again leaving everything unchanged and click "OK" again, the value saved gets incremented to "cecece".
I am using MODX 2.2.0pl2 and have been able to reproduce the issue in current versions of Chrome, Firefox & Safari