- refine the use of the "active group item", with differential styling, and not clearing when we enter the tab view
- set the active group item in other cases, like when we drag out groups, when we resize or move a group, or when a group is a drop target
- removed new tab group (you may have to clear storage to get rid of your locked New Tabs group at the bottom of your screen)
- rm various special casing for the new tab group
- new tab experience for tabs-off-of-orphaned-tabs is implemented: they magically turn into a group, and it even snaps!
- broken: new tabs made with no active context
- broken: closing the last tab in a group: should go back to tab candy view
- broken: first run experience grouping of orphaned tabs
