Instances created via HModel are not reflected in the GUI

Moved from Bugzilla:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=563727

Ran Wei is looking at creating Hawk indices programmatically, and noticed that when an instance is created via HModel.create with the non-UI based HManager, the GUI would not update.

This is technically correct (users should take advantage of HUIManager instead), but really, we shouldn't have two HUIManagers: it's just asking for trouble.

We should refactor the code to make this foolproof.