Root View Controller gets changing after navigating from Main ViewController to another controller by push in swift

[anil-irestore]

I have signup view in my application. After signup completes, I have Mainview Controller and I am making that as RootViewController with Slidemenucontroller.

Its working fine, but, after I am navigating from MainViewController to some other viewcontroller by doing push, once I pressed on Slidemenucontroller home button, its showing last pushed viewconroller instead of mainviewcontroller.

Even I set slidemenuviewcontroller with rootviewcontroller as Mainviewcontroller.

And I am using SlideMenuControllerSwift library to show slidemenu in my application.

Here is my code

    // create viewController code...
    let storyboard = UIStoryboard(name: "Main", bundle: nil)

    let mainViewController = storyboard.instantiateViewController(withIdentifier: "MainViewController") as! MainViewController
    let leftViewController = storyboard.instantiateViewController(withIdentifier: "LeftViewController") as! LeftViewController

    let nvc: UINavigationController = UINavigationController(rootViewController: mainViewController)

    let navigationBarAppearace = UINavigationBar.appearance()
    navigationBarAppearace.tintColor = UIColor.white
    navigationBarAppearace.titleTextAttributes = [NSAttributedStringKey.foregroundColor:UIColor.white]

    leftViewController.mainViewController = nvc

    let appDelegate = UIApplication.shared.delegate as! AppDelegate

    let slideMenuController = SlideMenuController(mainViewController:nvc, leftMenuViewController: leftViewController)
    appDelegate.window?.rootViewController = slideMenuController
    // slideMenuController.delegate = self as! SlideMenuControllerDelegate
    appDelegate.window?.makeKeyAndVisible()

How to fix this?