Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.12
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-09-11 09:14, hash: rB1b6dd42803df
Worked: (newest version of Blender that worked as expected)
Short description of error
Not able to select bones for posing. Normally a "bone" icon will appear after selecting "pose" in the outliner to allow posing.
Exact steps for others to reproduce the error
Go to outliner.
Try to select "pose" to pose armature.
However when I select pose in the dropdown it will allow posing, it will also reflect on the outliner (but we still can't use outliner to turn it off or on, like before).
Screencap after the dropdown select: