Group Policy ADM - Hide TightVNC tray icon

Save the following using a text editor as "vnctrayicon.adm" :

;Policy to hide tightvnc system tray icon on computer
;VALUE 0 = ICON VISIBLE
;VALUE 1 = ICON HIDDEN

CLASS MACHINE

CATEGORY "VNC Tray Icon"

KEYNAME "SOFTWARE\ORL\WinVNC3"
POLICY "Hide VNC Tray Icon"
EXPLAIN "Hides TightVNC Tray Icon"
VALUENAME "DisableTrayIcon"
VALUEON NUMERIC "1"

END POLICY
END CATEGORY

Import into your GPO (it applies to the machine not user) and run:
"gpupdate /force /boot" on the client.

The setting only applies after rebooting the client and can be verified by checking that the following registry entry has been created/modified:

HKLM\SOFTWARE\ORL\WinVNC3\DisableTrayIcon REG_DWORD 1