A window exactly covering the display is promoted by Windows to a direct /
independent flip. OpenGL swaps issued from the render thread then stop
reaching the screen on NVIDIA drivers: the image freezes while the game keeps
running, and it comes back as soon as anything forces composition (taskbar,
another window, a tooltip). The borderless window is now one row taller than
the display (the extra row is off-screen), so it always stays composed.
test_window_fullscreen checks the new size.
Seen with R4 on an RTX 3060 (driver 576.57), Windows 11, render thread on.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Rkyma8rbyPiccs9n2bkyG6