Shoutbox

If Windows Media Player was not closd properly (e.g. crashed and ended itself, Ctrl+Alt+Deleted, etc etc) it will disable all of the plugins on the next load. This means it no longer communicates with Messenger about what music is playing. Every time WMP is not properly closed, you need to re-enable the plugin.

Also, the popups only appear for the first music Item you start playing, if you have a playlist or switch to another file mid-playing, it won't popup - that's not Messenger Plus!'s fault, that was hardcoded by Microsoft.