Operating system: Windows 10
Graphics card: NVidia GTX 960m
Broken: example: 2.80, git.4ef09cf937f2, blender2.8, 2019-2-2
As described by the tool tip, holding shift should measure thickness. But whether clicked or not, thickness is never measured.
Steps to reproduce:
Be sure left-mouse select is enabled.
Click the measure tool
Shift-click on the side of the cube.