System Information
Operating system: Linux-5.4.0-7634-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.100
Blender Version
Broken: version: 2.90.0 Alpha, branch: master, commit date: 2020-07-02 22:21, hash: rB5a13f682ee5f
Worked: version: 2.90.0 Alpha, branch: master, commit date: 2020-06-28 15:13, hash: rBb21ba5e57974
Short description of error
Materials preview does not appear in "Browse material to be linked" list.
It should show up at the left edge of the list.