     
     public func changeMainViewController(mainViewController: UIViewController,  close: Bool) {
         
-        removeViewController(mainViewController)
+        removeViewController(self.mainViewController)
         self.mainViewController = mainViewController
         setUpViewController(mainContainerView, targetViewController: mainViewController)
         if (close) {

    
    public func changeLeftViewController(leftViewController: UIViewController, closeLeft:Bool) {
        
        removeViewController(leftViewController)
        self.leftViewController = leftViewController
        setUpViewController(leftContainerView, targetViewController: leftViewController)
        if closeLeft {

    }
    
    public func changeRightViewController(rightViewController: UIViewController, closeRight:Bool) {
        removeViewController(self.rightViewController)
        self.rightViewController = rightViewController;
        setUpViewController(rightContainerView, targetViewController: rightViewController)
        if closeRight {
