Mouse is not captured when switching between clients when running PIE

If the user launches multiple clients with PIE, the mouse will only be captured by the last client launched. If the user Alt+tabs to another window than the mouse will not get captured and they will need to click and drag in order to move their camera

1. Open the editor
2. Set the number of clients to 3
3. Play in editor
4. Alt+tab to another client
5. Notice that the mouse is not captured
6. Switch back to the last client that was opened
7. Notice that the mouse is captured

Expected: The mouse would be captured by default for all windows
Result: The mouse is not captured for other windows (only the last window to open)