Similar to Disk Browser, Scopes; Pattern Editor, Mixer; DSPs, Automation, etc,
Implement additional tabs as canvas areas for Tools so they need not always be pop-up/pop-over windows.
It’s an interesting idea.
Has already been discussed quite a few times, too:
http://forum.renoise.com/index.php?/topic/26159-shouldnt-certain-tools-be-dockable/
http://forum.renoise.com/index.php?/topic/30784-dockable-tools/
Yeahhhh
I just +1ed all those topics 
I just +1ed all those topics also! 