Parent task to track UI work //required// to make Blender 2.8 releasable.
* T54628: sharing of workspaces
* Fix tool adjust popup glitches.
* Make topbar more useful by completing tool system
* T56599: improve statusbar keymap display.
* Add icons for new functionality.
* Viewport navigation icons update.
* T54858: command settings cleanup
* Tabs in N-key sidebar for addons to put commands (T55386)