Cannot assign material to an object or object face I'm a newbie, I'm using Blender 2.80 on Devuan Ceres Linux.
I'd like to create a sign object, which is super simple: an extruded cube makes up the pole section and another extruded cube is the sign portion. I try to assign material as I see it on various tutorials, but pressing the Assign button has no effect whatsoever.


I select a mesh face in Edit mode
On the material panel the right material is selected
I press Assign -> this should result in the material assigned to the face but nothing happens. Accordingly a render shows blacked out objects on the scene.


Video of the issue

The project file
You need to go to material preview mode