diff --git a/src/js/net/minecraft/client/GameWindow.js b/src/js/net/minecraft/client/GameWindow.js
index 1af33a3..9d0a202 100644
--- a/src/js/net/minecraft/client/GameWindow.js
+++ b/src/js/net/minecraft/client/GameWindow.js
@@ -131,6 +131,10 @@ window.GameWindow = class {
 
         this.mouseX = event.clientX;
         this.mouseY = event.clientY;
+
+        if (!this.mouseLocked && this.minecraft.currentScreen === null) {
+            this.requestFocus();
+        }
     }
 
 }
\ No newline at end of file