In our app's root MasterDetailpage we have a small piece in the constructor to tell it to behave as a SplitView on a Tablet.

        if (Device.Idiom == TargetIdiom.Tablet)
        {
            MasterBehavior = MasterBehavior.Split;
            Icon = "";      // Unfortunately this doesn't remove the icon.
        }

This is working great however the default arrow has returned on the navigation bar.

I have tried overriding the Icon in the NavigationPage, but that didn't seem to work.

public class StyledNavigationPage : NavigationPage
{
    public StyledNavigationPage(Page root) : base(root)
    {
        InitColors();
    }

    protected override void OnAppearing()
    {
        base.OnAppearing();
        InitColors();
        if (Device.Idiom == TargetIdiom.Tablet)
        {
            Icon = "";   
        }
    }

    private void InitColors()
    {
        BackgroundColor = (Color)Application.Current.Resources["BaseBlue"];
        BarBackgroundColor = (Color)Application.Current.Resources["BaseBlue"];
        BarTextColor = (Color)Application.Current.Resources["LightBlue"];
    }
}

What might I need to do to remove the arrow icon? As it stands, it does not behave as a back button anyways.