Tabs under More ... not working

Hi,
My main application subclasses TabbedPage and I add tabs using the code below

NavigationPage helpPage = new NavigationPage(new HelpPage());
                helpPage.Title = "Help";
                helpPage.Icon = "Icons/Tabs/help.png";

                this.Children.Add (helpPage);

The HelpPage class subclasses the ContentPage class.

I observed that if the tab is amongst the first 4 tabs it works fine, listview clicks, button events and all. But if it isn't amongst first 4 and is under the More menu, it doesn't work (same class). Buttons don't work, listviews don't select, basically nothing works on the page.

How can I solve this pls?