I just landed a change today
that switches SeaMonkey to tabbed browsing by default. Umm, yes, that sounds like a message from years ago, but it really is of today.
The Mozilla suite has been supporting tabbed browsing for a very long time, and SeaMonkey inherited that support right from the start. Still, what we also inherited and had not even changed in our huge modernizing effort in 2.0 is that the default preferences favored opening new windows in all kinds of cases. Whoever wants to use tabbed browsing in stable version of SeaMonkey up to 2.0.x need to explicitely open tabs and/or change preferences to make SeaMonkey open tabs by default.
Finally, that changes with tomorrows nightlies, SeaMonkey 2.1 Alpha 3 and the final 2.1 release expected later this or very early next year (i.e. at a very similar time to Firefox 4).
From now on, SeaMonkey will default to open links and other new pages in tabs, just like Firefox already does. Anyone who still wants windows to be opened is now the one who needs to change preferences or do it explicitely.
Thanks to Neil for swift reviews on that preferences change. This is another step towards making SeaMonkey actually show that it really is a modern browser - and more.