In the latest version of Camera Raw try to add noise via the fx-tab. the size slider does not have any effect. Sorry, German Version. On Mac, everything updated. Moving the slider does nothing – everything else works as expected.
Ok, no i have the clue to specify it: The bug is in the FILTER version of Camera Raw, not the development-version for RAW. This version ist also missing the snapshot tab. By the way the Development-Version is working as expected! The version from the filter-menu ... not. But that's the version i am using more often.