Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.86
Broken: version: 2.80 (sub 74), branch: sculpt-mode-features, commit date: 2019-07-08 14:21, hash: rB3539cd38a454
Short description of error
As I am picking color from viewport pixels, not from VCOL data, it is almost impossible to match color (even with flat shading) and syringe become useless.
Exact steps for others to reproduce the error
Toggle vertex color mode, try to paint any color, then pick it with S and paint again