How to Enable Borderless Fullscreen in Minecraft with Cubes Without Borders

Switch the Fullscreen Setting

Open Minecraft and go to Options → Video Settings. Find the Fullscreen toggle. With Cubes Without Borders installed, this control now cycles through an extra state instead of only on/off. Click it until it reads Borderless. The game window will immediately resize to fill your monitor without a title bar or border, and it will no longer minimize when you click on another application.

If you prefer the vanilla-style exclusive fullscreen, keep clicking to return to the normal Fullscreen option. The Borderless state is the one that lets you alt-tab or click a second monitor freely.

Confirm It Is Working

After switching, click on a different window on your second monitor. Minecraft should stay visible and keep rendering. If it still minimizes, you are likely still in the standard Fullscreen mode — reopen Video Settings and cycle the toggle again until Borderless is selected.

Notes

The setting persists between launches, so you only need to set it once. If your resolution looks stretched, check that your in-game resolution matches your monitor's native resolution in the same Video Settings screen.