Window Messenger Tray Icon Disappears

[Jono]

Hello,

I've been experimenting with the two unofficial beta verions of MSN
Messenger & Windows Messenger.

Is there any reason (other than the fact it's a Beta version) that would
cause the Windows Messenger system tray icon to disappear, when I click on
the cross in the top right-hand corner of the main window?

The icon is only present when the main window is open, yet the program still
runs perfectly in the background.

Thanks in advance.

Jono.