Reproduction steps:
1. Open the attached “BugRepro” project
2. Enable the “Enter Play Mode Options” option (Edit > Project Settings > Editor)
3. Disable the “Reload Domain” option under “Enter Play Mode Options”
4. Open the UI Toolkit Event Debugger window (Window > UI Toolkit > Event Debugger)
5. Select the “New Panel Settings” panel in the UI Toolkit Event Debugger window
6. Enter the Play Mode
7. Move the mouse over the Game View
8. Observe the events in the UI Toolkit Event Debugger window

Expected result: Events are being fired
Actual result: Events are not being fired

Reproducible with: 2021.3.37f1, 2022.3.23f1, 2023.2.17f1, 6000.0.b14

Reproducible on: Windows 10
Not reproducible on: No other environment tested

Note:
- Workaround: Edit a script while being in the Play Mode. Exit to cause a reload and re-enter the Play Mode. The Events are being fired.