Sometimes, the right-click context menu from the tray is finicky. To replicate this, do this (Win XP Pro):
--place a window right above the system tray where the menu will pop-up.
--minimize and undock your launchbar so the only way to access it is with the tray icon
--right-click the tray icon, go to preferences.
--make some negligible change, then close the preferences.
--Now, try right-clicking on the tray again. The menu will flicker, but you'll have a hard time selecting anything because it doesn't stay open.
This happens 100% on my work computer. To recover, I either need to exit/restart. Or open the full menu, then minimize to tray again.