How to reproduce:
1. Create a new project in your preferred workspace and open it
2. Connect it to Perforce
3. Create 3 new scripts and submit them
4. Check out the middle script's .meta file and select the script
5. Now while holding Ctrl on the keyboard select the rightmost Script
6. Observe the Inspector Window's VCS button bar

Expected result: The Checkout button is always visible while there are files selected that could be checked out
Actual result: The Checkout button is missing

Reproduced in: 2020.1.0a3, 2019.3.0b3, 2019.3.0a4
Not reproducible in: 2019.3.0a3, 2019.2.5f1, 2018.4.8f1, 2017.4.32f1 (Had no Inspector version control buttons)