This patch removes a bunch of specific code for drawing the spreadsheet
data set region, which was an overly specific solution for a generic UI.
Nowadays, the UI tree view API used for asset browser catalogs is a much
better way to implement this behavior.
To make this possible, the tree view API is extended in a few ways.
Collapsibility can now be turned off, and whether an item should
be active is moved to a separate virtual function.
The only visual change is that the items are now drawn in a box,
just like the asset catalog.
Differential Revision: https://developer.blender.org/D13198
This patch adds a left aligned sidebar to the spreadsheet editor. This
Sidebar can be used to navigate the geometry component types and
attribute domains. It also provides a quick overview of domain sizes.
It replaces the two dropdowns in the regions header.
Next step will be to add the domain cycling shortcut
using the CTRL + mouse wheel.
Reviewer: Dalai Felinto (dfelinto), Julian Eisel (Severin),
Hans Goudey (HooglyBoogly).
Differential Revision: https://developer.blender.org/D11046
