How to reproduce:
1. Open the attached project ("ProviderSubmit".zip") and set it up to use Perforce's version control
2. Enter Play Mode and observe the Version Control Window
3. Focus a different program and then refocus Unity
4. Observe the Version Control WIndow again
5. Stop the Play Mode, check out the TestMe script and re-enter Play Mode
6. Right-click the TestMe script -> Version control... -> Submit...
7. Observe that the file isn't found in the same way until the Editor is refocused

Expected result: The Version Control/Version Control Changeset windows immediately show a new pending change
Actual result: The Version Control/Version Control Changeset windows aren't updated until the editor is refocused (clicking on any other program and refocusing Unity solves the issue)

Reproduced in: 2019.2.0a10, 2019.1.0b9, 2019.1.0a10
Not reproducible in: 2019.1.0a9, 2018.3.11f1