Everything above this blog post are new to ADT 12, and everything below it are included in ADT 11.
We've fixed a number of smaller issues in ADT 12 that don't deserve blog posts on their own, but here's a quick roundup:
* Several important bugs related to the GestureOverlayView have been fixed.
* Code completion inside a custom view layout has been improved
* The proguard template has been tweaked such that it should no longer remove classes that are only referenced from XML
* A problem with the property sheet not updating itself in Eclipse 3.6.2 has been fixed (and we improved the sorting of its categories)
* Fragment-rendering inside included layouts has been fixed