First of all, this seems to be no duplicate! On Ubuntu 13.04 whitelisting systray icons with dconfig-Editor and terminal commands seem to be no working.
I marked "hide vidalia at startup", so the systray icon disappeared, but there seems to be no way to open it again, to close vidalia properly. At next startup an error message pops up, that it is already running.
Published solutions didn't work, because dconfig doesn't show panel and whitelist options. Terminal says: «com.canonical.Unity.Panel» doesn't exist.