STLock

STLock is a mouse boundary management tool for multi-monitor Windows environments. It keeps the cursor locked within the screen you are currently working on, preventing the pointer from accidentally sliding onto another display. When you need to cross to another monitor, just hold the Ctrl key to temporarily lift the restriction; release it and the cursor relocks to whichever screen it is on. STLock automatically detects display topology and relocks within seconds when monitors are connected or removed, and it can optionally auto-start in the background after Windows login, residing in the system tray with a low memory footprint. The interface is available in eight languages: Traditional Chinese, English, Japanese, Korean, Simplified Chinese, Spanish, French, and German. Requires Windows 10 (64-bit) or later. The free version is functionally identical to the paid version.