Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.07
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Short description of error
Create a half mesh with a mirror and skin modifier.
enter weight mode try to use the gradient tool for vertices not on the mirror plane.
note: left click painting works fine. just the gradient weight tools do not.
apply mirror and vertices can be effected by gradient tool.
Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]