If you have a multimonitor system and you set up windowed fullscreen mode then switching monitors works until the game loses focus. If you give the game focus again it switches back to primary monitor and you have to move it once more.
To reproduce:
- Change game to Windowed Fullscreen
- Use Win Key + Shift + Left/Right Arrow to switch monitors with the game
- Alt tab to another window (Like browser)
- Click back into WC3
Result - Game will switch monitors
Expected Result - Game remains in selected monitor