Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 980 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 436.15
Broken: version: 2.81 (sub 8), branch: master, commit date: 2019-09-06 17:15, hash: rB7cec119c576b
Short description of error
When selecting a Bone Group Color set and then reverting it to default, the preview colors of the last color set remain in the UI.
Exact steps for others to reproduce the error
Create Armature, add a second bone. Enter Pose Mode, select both and add them to a new Bone Group. Select a different color set. The new colors appear to the right of the dropdown. Then select Default Colors again. The colors right of the dropdown stay unchanged but the bones in the viewport revert to the standard display color.
What it should do: when selecting Default Colors again, revert the preview colors to default as well.