Reproduction steps:
1. Open a new or an existing project
2. Make sure Scene View is not in focus (press on the Hierarchy window if it is)
3. Press Alt and try to use Orbit or Zoom controls with the mouse buttons

Expected result: Orbit and Zoom controls work as expected
Actual result: Orbit and Zoom controls do not work until Scene View is in focus

Reproducible with: 2019.4.0f1, 2020.1.0a1, 2020.1.2f1, 2020.2.0a11
Not reproducible with: 2018.4.26f1, 2019.4.1f1, 2020.2.0a12

Note:
- 2020.1.1f1 and up, after releasing the Alt button, the Hand tool gets stuck in Orbit and Zoom control mode until the Scene View is not in focus anymore (regardless if it was in focus earlier)