There were lot of voices against the replacement of categories with pagination, and that was another controversial feature originally planned for Gnome 3.6.
Guess what. It won’t happen.
We won’t see the above figure, or more correctly will see the half of it!
There were some reasons why Gnome developers discussed and decided to drop categories, and I personally was over it, not fanatical over it, but sure I was in favor. Most of people seem to be against that move, and Gnomers listened to these complains and changed direction (at least for now!). Yeap it is better to allow people to personalize their applications in an OS. Yes Gnome3 is moving to a complete core but not isolated (no Gnome OS distro) Operating System.
And the good news continue. Gnome will ship the newApplication Launcher (if not having any surprises!):
“Overview allows to switch between running applications, open windows and *launching new apps*. Initial design introduced a tab-like interface, expecting new categories to be introduced (Finding & reminding). That functionality has moved to the Applications themselves now. The tabs are hard click targets and spatially inappropriate.”
It is super true that Gnome extension contributors avoided to use Gnome Shell tabs for their extensions. I think that only Journal extension was working there, but they moved this functionality on the new App Launcher. So no need for them (Tabs).
I won’t risk to describe how this new “icon” works as its features aren’t quite clear, but you can see an animation/video demo here: http://jimmac.fedorapeople.org/gnome3/modeless-overview-scrolled-view.webm.