If you haven't, heres a user exercise. Go to xcode and see what you can get done with an NSTabView... go head, I'll wait.
If you want a hint, here is what you can do.
But finally, some smart guy has come to rescue us from our misery.
Rasmus Anderssonyou are my new hero.
Rasmus is the primary developer for Kod - a Mac based programmers editor. As part of Kod, he has developed a project called Chromium-Tabs, which basically gives programmers a nice - easy to use - API for creating beautiful browser like tabs (some say they look like Chrome).
So, I've promptly made a makefile so I dont have to deal with that nasty xCode IDE (yuck!), and integrated the Chromium-Tabs framework into my CodeAssistor project. Now I have a nice beautiful looking TABBED editor :)
All in all, the makefile took me 5 hours, and learing-integrating chromium tabs into codeassistor took 14/15 more.
If you want to play with the Alpha release of 0.0.8 (Mac Only so far), here you go
EDIT: Kod and Chromium Tabs Source