Operating system: Linux-4.15.0-47-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 410.73
Broken: version: 2.80 (sub 64), branch: blender2.7, commit date: 2019-05-14 22:59, hash: rB4e46ed37fc59
Description of error
Some buttons of the 3D View header are overlaping the Tool Settings bar, cutting it in half and negating a lot of space that may be needed for active tools that require such space.
It also creates conflicts when flipping the header to the bottom of the 3D View, as these buttons stay inside the Tool Settings bar, regardless of the rest of buttons.
This doesn't happen with the other header buttons like the current object mode, menu buttons, object type visibility, viewport gizmos, viewport overlays and shading buttons.
Current state of the Tool Settings bar
How it should be.