Do you run Opera at all? If so, it isn't checked by default.
And do you have "Adobe Flash Player" checked in "Applications\Multimedia"? Quite a number of cookies are now "Flash Cookies" (settings.sol files).
An example:
I don't have that problem with Firefox 3.5.5 (haven't updated to 3.5.6 yet), so I can't replicate it myself.
Hope that helps.
Something must have changed. I can get the cookies to show up on the left pane - only if I uncheck the box the says clean cookies. Previous versions of ccleaner I didn't have to do that.
I could have FireFox running - go to a site that I know I would want to keep the cookie, and even with the ccleaner box checked to clean cookies - it would show them - with FireFox up and ccleaner running - I would then just move the cookie from the left pane to the right.