Losing focus of the game window can cause the screen to briefly turn fully black even with the "Exclusive Fullscreen" option disabled

Regardless of whether Exclusive Fullscreen is enabled or disabled, Minecraft always enters Exclusive Fullscreen mode when fullscreen is enabled.

Steps to Reproduce

1. Launch Minecraft 26.3 Snapshot 4 or 26.3 Snapshot 5.

2. Go to Options → Video Settings.

3. Make sure Fullscreen is On and Exclusive Fullscreen is Off.

4. Let the game window lose focus (for example, press the Windows key or use Alt+Tab to switch to another window).

Expected Result

The game should behave like a normal borderless/windowed fullscreen application, switching focus immediately without a display mode change.

Actual Result

The screen briefly goes black before displaying the other window, indicating that Minecraft is still using Exclusive Fullscreen.