public void LaunchApp(KeyboardApp app)
        {
            //Suspend active app
            if (apps.Count > 0)
            {
                apps[apps.Count - 1].OnAppSuspended();
                apps[apps.Count - 1].hidden    = true;
                apps[apps.Count - 1].suspended = true;
            }

            //Start
            frame.children.Add(app);
            apps.Add(app);
            app.OnAppLaunched();
            app.OnAppResumed();
            app.suspended = false;
        }
        public void CloseApp(KeyboardApp app)
        {
            //Get the index
            int index = apps.IndexOf(app);

            //Close it
            if (!app.suspended)
            {
                app.OnAppSuspended();
            }
            app.OnAppClosed();
            frame.children.Remove(app);

            //If this is the active app and there are other apps, open the next one
            if (apps.Count > 1 && index == apps.Count - 1)
            {
                apps[apps.Count - 2].OnAppResumed();
                apps[apps.Count - 2].hidden    = false;
                apps[apps.Count - 2].suspended = false;
            }

            //Remove this app from the list
            apps.Remove(app);
        }