This is the first step to moving redo out of the top-bar, see: T55039
- Support for floating panels in the ScrArea has been added.
- A new region type RGN_TYPE_HUD is used for floating settings input.
- Only one HUD should be visible at a time.
- Currently HUD regions are only visible
for 3D view and image space types.
- There are currently some remaining glitches with hide/show
that need further investigation.