Operating system: Windows 10
Graphics card: Nvidia GeForce RTX 2070
Broken: 2.8 91a155833e59
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Short description of error
Whenever I alt+tab to another application, like a tutorial on youtube to pause it, and I get back to Blender with the intention of panning the viewport with shift+middle mouse button, Blender ignores that I hold the shift key and rotates the viewport instead as if I only pressed midmouse button.
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Step 1: make the blender window inactive by alt+tab to another application. Make sure that the other application doesn't cover the entire screen, and your blender viewport is still visible.
Step 2: Shift+MiddleMouseButton into the visible blender viewport. Instead of the expected panning behaviour you will rotate the viewport, as Blender ignores that you are holding Shift.