I use Messenger Plus! Live for one reason. Tabbed chat windows, and auto-file-download-accept-thingy. Ok, 2 reasons... But anyways, when tabbed chat is enabled, I enable it for all chats automatically, etc... And all the chats are grouped just fine, however, when I get a new message the button on the task bar doesn't flash. Sometimes, the actual tabs won't flash either, say when I'm typing to one person, and some one else that I already have a tab for sends a message, it won't blink. So I have to constantly cycle through all the tabs to see if I missed anything, which kinda defeats the purpose. This happens on any Vista system that I use, with the latest Messenger Live and latest Messenger Plus builds. Even earlier versions of Messenger Live cause the same problems in Vista.
Windows Vista 32 bit - tested on Ultimate, Business, Enterprise.
Thanks for the awesome product, sadly I won't be using it until this works again.