Note, this was reported as a bug however it's a TODO (wasn't supported in 2.7x).
Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.39
Broken: version: 2.80 (sub 60), branch: master, commit date: 2019-04-29 17:52, hash: `rB047081841113`
Worked: (version before the click transparent passthrought)
**Short description of error**
Cannot drag on the tabs to select other tab like normal tab behavior on Blender.
**Exact steps for others to reproduce the error**
-Press 'N' on the 3D View.
-Try to drag on the tabs on the "WM_OT_context", the result is the box selection.
See attached gif (ignore the mouse cursor offset, that is due to 4k display with only 125% scale applied.)