System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 445.87

Blender Version
Broken: version: 2.90.0 Alpha, branch: master, commit date: 2020-06-04 22:58, hash: rBc7329da14b22
Worked: (newest version of Blender that worked as expected)

Short description of error
At the start knife tool do not show tooltip, overlays and do not react to modifier keys. So I can`t start to cut from center of the edge for example.
looks like it need hotfix