Master Detail Page Back Button

At first, I made my project using this site
And i can navigate ohter pages through master(hamburger menu)

This is my question.
If i tapped a row of datagrid at ClientPage, it will navigate to ClientDetailPage.
And i can return ClientPage by clicked Navigation Back Button, But!! Hambuger menu icon is disappeared...

//MainPage.xaml
public MainPage()
{
InitializeComponent();
IsPresented = false;
menuList = new List();

            var page1 = new MasterPageItem() { Title = "Client Management", Icon = "ic_import_contacts_black.png", TargetType = typeof(CleintManagementView) };
            var page2 = new MasterPageItem() { Title = "WOD Management", Icon = "", TargetType = typeof(WODManagementView) };
            var page3 = new MasterPageItem() { Title = "Statics", Icon = "", TargetType = typeof(Statics) };

            menuList.Add(page1);
            menuList.Add(page2);
            menuList.Add(page3);

            MenuList.ItemsSource = menuList;
            Detail = new NavigationPage((Page)Activator.CreateInstance(typeof(CleintManagementView)));
}
        #region MasterDetail MenuList Selected
        private void MenuList_ItemSelected(object sender, SelectedItemChangedEventArgs e)
        {
            var item = (MasterPageItem)e.SelectedItem;
            Detail = new NavigationPage((Page)Activator.CreateInstance(item.TargetType));
           IsPresented = false;
        }

//ClientPage
private void dataGrid_GridDoubleTapped(object sender, Syncfusion.SfDataGrid.XForms.GridDoubleTappedEventsArgs e)
{
var masterDetail = App.Current.MainPage as MasterDetailPage;
var nav = new NavigationPage();

            var nextPage = new ClientManagementDetailView();
            var selected = e.RowData as People;
            nextPage.BindingContext = selected;
            nextPage.PassContext();
            masterDetail.Detail.Navigation.PushAsync(nextPage);
        }

ClientPage

ClientPage->Double Tapped->ClientDetailPage

Hamburger menu is disappeared..