protected override void OnSizeAllocated(double width, double height)
    {
        base.OnSizeAllocated(width, height);

        (this.drawer.DrawerContent as IView)?.InvalidateMeasure();
        (this.drawer.MainContent as IView)?.InvalidateMeasure();

        this.Dispatcher.Dispatch(() =>
        {
            var platformView = this.drawer?.Handler?.PlatformView as TelerikUI.TKSideDrawerView;
            if (platformView != null)
            {
                var hostView = platformView.MainView.Superview;
                if (hostView != null)
                {
                    var layer = hostView.Layer?.Sublayers?.LastOrDefault() as CALayer;
                    if (layer != null)
                    {
                        layer.Frame = new CoreGraphics.CGRect(0, 0, hostView.Frame.Width, hostView.Frame.Height);
                    }
                }
            }
        });
    }

private void OpenDrawer_Clicked(object sender, EventArgs e)
    {
        this.drawer.IsOpen = true;
        (this.drawer.DrawerContent as IView)?.InvalidateMeasure();
    }

public partial class MainPage : ContentPage
{
	RadSideDrawer drawer;

public MainPage()
	{
		InitializeComponent();
		this.drawer = new RadSideDrawer();
		this.drawer.HandlerChanged += drawer_HandlerChanged;
	}

	private void OpenDrawer_Clicked(object sender, EventArgs e)
	{
		this.drawer.IsOpen = true;
	}

	private void drawer_HandlerChanged(object sender, EventArgs e)
	{
		this.UpdateDrawer();
	}

	private void UpdateDrawer()
	{
		var platformView = this.drawer.Handler.PlatformView;

#if IOS || MACCATALYST
        var platformSideDrawer = (TelerikUI.TKSideDrawerView)platformView;
        var drawer = platformSideDrawer.SideDrawers[0];
        drawer.Style.HeaderHeight = 0;
        drawer.Style.FooterHeight = 0;
#endif
	}
}