Followup task to T54653 to work on implementing the workflow changes proposed.
(Note: This is currently a lower priority item than fixing bugs to get 2.8 into a usable state for Spring team. But, I'll be working on this when I get time).
There are the following sub-tasks:
* ~~**Create operator for "Open Drivers Editor" functionality.**~~ rBc685c19df95
* ~~Basic opening functionality~~
* ~~Filtering support to get driven property under mouse at the time the "active" driver~~
* Abstract out the "Setup Drivers Editor" and "Show this channel" functionality
* Sub-editor mode for drivers in the mode selector
* **Eyedropper support for clicking in 3D view and getting menu of common properties to drive, based on item under mouse.**
* Basic object support
* Investigate possibility of bone support too. (NOTE: Last time this was tried, it turned out being too complex to accomplish)
* Restore cursor feedback when eyedropper is active (T55147)
* Solve context/src button problems preventing eyedroppers from working in the popover
* **Clean up drivers editor ui** - rB57b47ebb284 (and followup commits)
* ~~Add more space for expressions box~~
* ~~Remove "Show Debug Info" checkbox - it's always needed~~
* ~~Remove "Update Dependencies" button by making it redundant~~ - Should be ok now without out. It's still in the UI, but will be removed soon
* Remove "Use Self"? Or rename?
* Add optional display of useful hints about syntax for expressions and/or what can be used
* **New persistent floating panel UI for editing driver settings**
* ~~Basic layout~~ - rB7e7680e33bb - Use a modified version of the existing drivers editing panel, and make it a popover
* ~~Floating panel~~ - rB7a88a7742b5 - This makes the panel a popover. But, it doesn't stay open, or let you open the drivers editor
* ~~Make floating panel stay open~~ - rBb11a1d5da26
* ~~Get "Open Drivers Editor" button working in the popup (i.e probably missing button context info for source property)~~ - rB1ff28c2650a
* Get Copy/Paste dvar operator buttons working (currently always greyed out)
* ~~Fix issues where popover still goes away too easily sometimes~~ - Seems to be fixed with rB17ee4836aba now. It may still happen, but it happens a whole lot less now.
* **Reduce friction of adding new driver variables / setting up basic single-target drivers **
* ~~Replace 'Add Drivers' Menu with Popover Panel ~~ - rB4605e57b0f6
* Remove old (menu-based) operator
* "Mapping" settings properties (see proposal)
* ~~Make setting driver input-target easier~~ (i.e. no more need to change default expression first) - rB9ab26bec276
* Eyedropper for populating input variable settings (see above)