Stop your mouse moving onto the second monitor while gaming

You flick the mouse in a borderless game and the cursor slides onto your other monitor. One click there and the game loses focus.

Why it happens

In exclusive fullscreen the game owns the display, and the cursor rarely escapes it. Borderless and windowed games are ordinary windows on a desktop that spans every screen, so unless the game confines the cursor itself, and many only do while you are aiming, nothing stops it crossing to the other monitor.

Free fixes first

1. Look for "Confine mouse", "Lock cursor to window" or similar in the game's display or controls settings.
2. Rearrange your displays so the screens only touch along a short stretch of edge. In Settings, System, Display, drag the second monitor so it meets the game's screen near a corner, and the cursor can only cross there.
3. Exclusive fullscreen usually keeps the cursor in, at the cost of the game minimizing whenever you click away.

When the free fixes are not enough

Few games offer a confine option, a lopsided display arrangement makes moving between screens awkward for everything else, and exclusive fullscreen brings the minimizing back.

How Second Screen Gaming fixes it

Keep the mouse on this screen is an option of Run borderless on a chosen screen. While the game is the window in front, the cursor stays on the game's monitor.

Press Alt+Tab or the Windows key and the game is no longer in front, so the mouse is free to cross to your other screen. It is held again when you return to the game.

Games that lock the cursor more tightly themselves, to their own window or to a crosshair, keep their own lock.