Because it is native to Windows Live Messenger 2011 there was no sense including it because a native implementation is always better and less buggy than a hack implementation. If you downgrade Windows Live Messenger to a previous version without the tabbed chats the Messenger Plus! option will become available.
Tabbed Chats - by Soil3d on 08-09-2011 at 10:07 AM RE: Tabbed Chats - by matty on 08-09-2011 at 10:56 AM RE: Tabbed Chats - by qwerty2 on 06-21-2012 at 05:53 PM RE: Tabbed Chats - by woodenflashlight on 10-13-2012 at 12:24 AM
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