RTS locked/unlocked camera

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var CamSpeed = 1.00;
var GUIsize = 25;
var target : Transform;
var cameraLocked : boolean = false;

function OnGUI () {

    if (GUI.Button (Rect (Screen.width / 2,Screen.height / 2,120,20), "Lock Camera")) {
        cameraLocked = !cameraLocked;
    }
}

function Update () {

    if(Input.GetKeyDown("left shift")) {

        transform.position.x = target.transform.position.x;
        transform.position.z = target.transform.position.z -50;
    }

    if(cameraLocked == false) {
        var recdown = Rect (0, 0, Screen.width, GUIsize);
        var recup = Rect (0, Screen.height-GUIsize, Screen.width, GUIsize);
        var recleft = Rect (0, 0, GUIsize, Screen.height);
        var recright = Rect (Screen.width-GUIsize, 0, GUIsize, Screen.height);

        if (recdown.Contains(Input.mousePosition))
            transform.Translate(0, 0, -CamSpeed, Space.World);

    if (recup.Contains(Input.mousePosition))
            transform.Translate(0, 0, CamSpeed, Space.World);

    if (recleft.Contains(Input.mousePosition))
            transform.Translate(-CamSpeed, 0, 0, Space.World);

    if (recright.Contains(Input.mousePosition))
            transform.Translate(CamSpeed, 0, 0, Space.World);
     }


    else if(cameraLocked == true){
        transform.position.x = target.transform.position.x;
        transform.position.z = target.transform.position.z -50;
    }
}