In Blender, the selection state is not shared between the Outliner and the scene. This is inconvenient and often impractical, but it’s also confusing. If you select something in the viewport, the same object is not selected in the Outliner. But if you select something in the Outliner, it overrides the selection inside the viewport. The selection is synced one way but not the other. It’s half syncing in a confusing way.
It also means that we need two confusing ways of showing selections - the highlighted row and the icon circle.
I think we can make this a lot easier to use. Here’s how:
We add a toggle inside the Filter popover called Synced Selection, just like we have in the UV Editor. This should be on by default.
Synced Selection: On
With this option on, the selection state is shared between the Outliner and the viewport. This makes everything simpler, because users don’t have to worry about selecting things twice. If something is selected, it’s selected in both Outliner and viewport, always.
One of the great benefits of this, is that we then don't need two separate selection states inside the Outliner, which makes it much simpler to read and understand.
Synced Selection: Off
With this option off, the selection state is completely decoupled, rather than the current half-syncing system that tries to only sync one way. This could mainly be useful if you have multiple Outliners with different selections.
These changes should make selection in the Outliner a lot more straight forward, in a way that’s both more efficient and less confusing in the vast majority of use-cases.
When simply selecting objects in the Outliner, it's easy to figure out what to do. But there are other cases where it's not so clear:
|Outliner Selection||3D View Result|
|Sub-element of object (obData, material etc) in Outliner||Select the object they are attached to|
|Collection in Outliner||Select containing objects|
|View Layer in Outliner||Deselect all objects|