Screen.lockCursor mystery?

I’m using this simple code on my custom FPS character controller:

void Start() {
    // Lock Cursor
    Screen.lockCursor = true;

I just want the mouse cursor to stay frozen where it is (ie: always in the center of the screen). I can not understand why the above doesn’t work. It has literally no effect on the mouse cursor, I get the same with or without it.

Unity has a strange Bug where lockCursor refuses to work in the developer, but almost always works in the standalone/web version. Try building a standalone executable (or app, if on a mac) and try it from there. If it refuses to work there as well, try adding an update function to lock the cursor for OnMouseDown.