Hi Franco,
I changed it so that the tabs are now disabled by default; mainly because I was seeing too many live sites where they were unnecessary. It was clear that people simply did not know how to disable them, or never even knew they could.
Look for the tabbedcontent.flag setting in the Back Office to enable them.
There's a thread of release notes here:
http://nbstore.codeplex.com/discussions/407311
Regards
Rob