For some users of OS X, the Help > What's This? command may not function properly. This issue has been traced to a problem within the Adobe Air 3.9 framework itself and Adobe has been notified of the issue.
Until it has been corrected by Adobe however, users can revert back to Adobe Air 3.8, which does not have this issue. After uninstalling Adobe Air 3.9, users can download the 3.8 installer from this location.
After reinstalling, reboot your machine and then you should be able to use the "What's This?" command as expected.
This issue does not affect Windows users.
Edited by JimW