Vertical tabs are finally in Drupal core!
Screenshot of vertical tabs on an 'Article Edit' page in Drupal 7.
A week ago Angie "webchick" Byron committed a large patch from #323112 Vertical Tabs to Drupal 7 core. This change is quite possibly the most significant usability enhancement to Drupal 7 to date. Two of the three formal usability tests did usability testing with vertical tabs and reported positively.
Screenshot of a 'Story Edit' page in Drupal 6, before vertical tabs.
UPDATE: Rob Loach has created a patch to implement vertical tabs on the node-type form.
UPDATE: See other issues about vertical tabs in Drupal core .
What is more interesting about this however, is the process, time and effort that it took to get this change into Drupal core. It all started over a year ago, well before DrupalCon Boston 2008 even before Drupal 6 had a stable release. The discussion around part of that patch goes back as far as November 2007! Along the way countless people have been involved in many discussions, worked on heaps of mockups, lots of prototypes, and loads of code.