How to show separator for Xamarin.Forms Expander (SfExpander)

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:ExpanderXamarin"
             xmlns:syncfusion="clr-namespace:Syncfusion.XForms.Expander;assembly=Syncfusion.Expander.XForms"
             x:Class="ExpanderXamarin.MainPage" Padding="0,15,0,0">
 
    <ContentPage.Resources>
        <ResourceDictionary>
            <local:ExpanderIconConverter x:Key="ExpanderIconConverter"/>
            <local:SeperatorVisibilityConverter x:Key="SeperatorVisibilityConverter"/>
        </ResourceDictionary>
    </ContentPage.Resources>
    
    <ContentPage.Content>
        <ScrollView BackgroundColor="#EDF2F5">
            <StackLayout>
                <syncfusion:SfExpander x:Name="expander1" HeaderIconPosition="None">
                    <syncfusion:SfExpander.Header>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="50"/>
                                <RowDefinition Height="2"/>
                            </Grid.RowDefinitions>
                            <Grid>
                                <Label Text="Veg Pizza" TextColor="#495F6E" VerticalTextAlignment="Center" Margin="10,0,0,0"/>
                                <Image Margin="10" HorizontalOptions="End" HeightRequest="15" WidthRequest="15" Source="{Binding IsExpanded,Source={x:Reference expander1},Converter={StaticResource ExpanderIconConverter}}"/>
                            </Grid>
                            <BoxView Grid.Row="1" IsVisible="{Binding Path=IsExpanded, Source={x:Reference expander1}, Converter={StaticResource SeperatorVisibilityConverter}, ConverterParameter='Header'}" BackgroundColor="Green"/>
                        </Grid>
                    </syncfusion:SfExpander.Header>
                    <syncfusion:SfExpander.Content>
                        <Grid BackgroundColor="#FFFFFF">
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"/>
                                <RowDefinition Height="2"/>
                            </Grid.RowDefinitions>
                            <Label BackgroundColor="#FFFFFF" HeightRequest="50" Text="Veg pizza is prepared with the items that meet vegetarian standards by not including any meat or animal tissue products." TextColor="#303030" Margin="10,10,10,10" VerticalTextAlignment="Center"/>
                            <BoxView Grid.Row="1" IsVisible="{Binding Path=IsExpanded, Source={x:Reference expander1}, Converter={StaticResource SeperatorVisibilityConverter}, ConverterParameter='Content'}" BackgroundColor="Green"/>
                        </Grid>
                    </syncfusion:SfExpander.Content>
                </syncfusion:SfExpander>
            </StackLayout>
        </ScrollView>
    </ContentPage.Content>
</ContentPage>

public class SeperatorVisibilityConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if((string)parameter == "Header")
        {
            return (bool)value ? false : true;
        }
        else
            return (bool)value ? true : false;
    }
 
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}