You know, people always come here and ask how they can unlock Messenger. We teach to them then new ones come, and I think there will be always people who ask this question because everytime a new guy meets Messenger Plus! and when sees "Lock Messenger" item in Plus! menu, he wants to lock it without thinking how he will unlock it.
So a tip window can be very useful, just like the Messenger Lock Shortcut window, which pops-up when the user firstly presses the key combination which locks Messenger.
[Important edit: The window which I suggested in this thread will not popup when user presses the Messenger Lock Shortcut for the first time, but it will popup when user
locks Messenger by any way (either with shortcut or Plus! menu item) for the first time.
So I played with that window and made it suitable for such a feature. I know there must be some other things, like to what icon user changes Messenger systray icon, or does Ctrl need to be hold when double clicking on it, but I'm sure you can overcome it.
The time to implement this feature is not too late, whenever this is implemented, people will benefit it for sure.