Mac, Snow Leopard, InDesign CS5.5
I had white text (set using the "paper" swatch) with colored backgrounds. White should always knock out, never overprint. I did not change the paper swatch in any way. But both pdf and overprint preview don't show the white text. So I check Attributes>>Overprint. Sure enough, overprint is checked for the paper swatch, but the dialog is greyed out so I can not uncheck it.
I decide to make my own white (0c,0m,0y,0k) swatch and change the knocked out type to that swatch. That swatch seems to work for a few seconds, so I change my paragraph styles to use it instead of paper. Then it also defaults to overprint and is greyed out. (Arrgh!)
I change the text to some other random color swatch. The overprint checkbox becomes clickable, so I uncheck it and then select the 'paper' swatch to change the text back to white. This time it works: the overprint checkbox stays unchecked.
Anyone seen this behavior before? Causes or fixes?