See http://clumens.fedorapeople.org/UI/ui-tech-notes.

* UI design - CHECK
* Code architecture (base classes, etc.) - CHECK
* Design is flexible - CHECK
* Testability -
* Use GtkBuilder for everything - PARTIAL CHECK
   There's still some manual Gtk coding (creating the Category grid and the
   Hub box), but I don't see a way around it that makes things better.  Could
   use GtkBuilder but is a blob of inlined XML easier to understand?  Probably
   not.
* Decoupled from anaconda -
* Reduce number of dialog classes - PARTIAL CHECK
   Keep an eye on this.  So far, so good.
* Accessibility -
* Pre/post screen hooks -
* UI in its own thread - CHECK
* Batch up backend tasks - CHECK
* Share module format with firstboot -
* Organize source better - CHECK
* Automatic locale configuration -
* Don't store our own language list, font list, etc. - CHECK
* Simplify branding - PARTIAL CHECK
   You can easily add your own standalone windows, categories, and spokes to
   both custom categories and the ones we include.  How to do so is not yet
   documented.  You cannot add your own hubs (I don't see this as a problem),
   and there's no good way to change the look of the UI yet.
* UI writes out a kickstart file - CHECK
* Save in-progress file somewhere -
* Get rid of newt UI -
* Main loop - CHECK
* Widget usage statistics -