Minecraft Java Edition 26.2 Borderless Fullscreen Compatibility

Online Alias: ItzSlacks
Date: August 26, 2026

Abstract

This research documents fullscreen and Windows integration issues observed while running Minecraft Java Edition 26.2 on Windows with AMD graphics.

The investigation was prompted by problems with Exclusive Fullscreen, particularly Windows-key and application-switching behavior. The investigation is also relevant to MC-309872, a Mojang bug concerning problematic behavior when pressing the Windows key during Exclusive Fullscreen on affected configurations.

Cubes Without Borders (CWB) was tested as an alternative fullscreen solution. The initial configuration improved Alt+Tab behavior but did not completely resolve Windows integration. Switching CWB to windows:windowed produced substantially better results.

1. Initial Problem

The original configuration showed:

• Problems when switching applications in Exclusive Fullscreen

• Incorrect Windows-key behavior

• Minecraft potentially minimizing when losing focus

• A brief visual flash when changing windows

• Poorer integration with Windows interface elements

The tested system uses AMD graphics. AMD is therefore relevant to the tested configuration and to reports surrounding MC-309872, but this research does not establish AMD as the sole cause.

2. Cubes Without Borders

CWB was installed to provide a fullscreen appearance without relying on traditional Exclusive Fullscreen.

The initial configuration produced improvements:

• Alt+Tab worked

• Minecraft remained open when switching applications

• Minecraft no longer unexpectedly minimized

However, the Windows key still did not behave correctly.

Further testing identified CWB's windows:windowed implementation as the important configuration change.

3. Final Configuration

ComponentConfigurationMinecraftJava Edition 26.2GraphicsAMDFullscreen solutionCubes Without BordersImplementationwindows:windowedVSyncEnabledDisplayBorderless fullscreenWindow managementWindows-managed

VSync remained enabled to avoid screen tearing.

4. Compatibility Testing

Alt+Tab: Working. Minecraft remains open while switching applications.

Windows key: Working. The Windows interface can be opened without the previous fullscreen behavior.

Start menu: Working. The Start menu appears over Minecraft without minimizing the game.

Windows notifications: Working. Notifications appear over Minecraft.

Medal Overlay: Working. Medal's overlay successfully appears over Minecraft.

Picture-in-Picture: Working. PiP windows can appear over Minecraft.

Discord Overlay: Not working. Discord Overlay was enabled, but it did not appear. Since Medal Overlay works under the same configuration, this may indicate a Discord-specific compatibility issue rather than a general inability for overlays to appear. The exact cause has not been confirmed.

5. Startup Behavior

Minecraft initially launches in a small window and then automatically transitions into the configured fullscreen state.

Observed sequence:

Minecraft launches → small window → CWB initializes → fullscreen

This does not prevent the final configuration from working, but it is a noticeable startup quirk.

6. Results

FeatureResultBorderless fullscreenWorkingAlt+TabWorkingWindows keyWorkingStart menuWorkingNotificationsWorkingMedal OverlayWorkingPicture-in-PictureWorkingDiscord OverlayNot workingVSyncWorkingStartupSmall window before fullscreenExclusive FullscreenAvoided

7. Interpretation

The results suggest that the fullscreen appearance itself is not necessarily responsible for the Windows integration problems.

The underlying window-management method appears to be important.

The successful configuration effectively allows Minecraft to occupy the entire screen while remaining a Windows-managed window, allowing Windows interface elements and supported external windows to appear above it.

This differs from Exclusive Fullscreen, where Minecraft has greater control over the display.

8. Reproduction / Workaround

1. Install Minecraft Java Edition 26.2.

2. Install Cubes Without Borders.

3. Enable its fullscreen functionality.

4. Set the implementation to windows:windowed.

5. Keep VSync enabled if screen tearing is undesirable.

6. Test Alt+Tab and the Windows key.

7. Test Windows notifications, Start menu, Medal Overlay, and PiP.

8. Test Discord Overlay separately.

The resulting configuration provides a fullscreen appearance while retaining Windows-managed window behavior.

9. Conclusion

Testing indicates that CWB's windows:windowed implementation provides significantly better Windows integration than the tested Exclusive Fullscreen configuration on Minecraft Java Edition 26.2.

The configuration successfully supports:

• Borderless fullscreen

• Alt+Tab

• Windows key

• Start menu

• Notifications

• Medal Overlay

• Picture-in-Picture

• VSync

Discord Overlay remains non-functional, while Minecraft's brief small-window startup remains a minor quirk.

The tested system uses AMD graphics, making the findings relevant to MC-309872, although this research does not prove that AMD hardware alone causes the reported issue.