System Information
Operating system: Windows 10 1809 Build 17763.379
Graphics card: GTX 1060 3GB

Blender Version
Broken: 2.80 Date: 2019-04-06 12:26 Hash: cc73d59ad580

Short description of error
Error or not, I've found myself trying to navigate, rotate around, in the viewport to suddenly think either the version of Blender I was using was borked or my mouse was. Turns out, the free clear space of the UI is effecting the navigation of rotating around, acting as if the menu is still there.

Exact steps for others to reproduce the error
Middle mouse button in the freespace in any scene where a toolbar would be at.