Windows 7: Messenger 2009, Strangest thing

im using build 7127 of win 7 for a while.
live messenger 2009 is configured to start-up with windows.
i checked in compatibility mode> windows vista sp1 so it will show an icon on the tray and not on the taskbar.
it worked beautifully until today.
i started the computer and the messenger is on the taskbar like it is pinned and the icon isn't in the tray.
checked the compatibility mode, it's still on windows vista, tried
everything from XP SP1 to vista SP2 but the behavior is the same.



i thought it was a fluke so i restarted my computer and there it was again on my taskbar instead in the tray.

what the hell is going on?
i can't think of anything i did to end up in this situation.
i'll be grateful for your thought about this issue.