[noesis] Assets/Scripts/MapEditor/Views/ShellView.xaml(24): Can't set 'VacuumBreather.Montreal.MapEditor.ViewModels.EnumComparisonConverter' on property 'Binding.Converter' of type 'IValueConverter'.

    /// <summary>
    ///     Converts a boolean to an enum value specified as the converter parameter.
    ///     Use to bind in a group of radio buttons to an enum property.
    /// </summary>
    /// <seealso cref="MarkupExtension" />
    /// <seealso cref="IValueConverter" />
    public class EnumComparisonConverter : MarkupExtension, IValueConverter
    {
        #region Constants and Fields

        private static readonly EnumComparisonConverter Instance = new EnumComparisonConverter();

        #endregion

        #region IValueConverter Implementation

        /// <inheritdoc />
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return value?.Equals(parameter);
        }

        /// <inheritdoc />
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return value?.Equals(true) == true ? parameter : Binding.DoNothing;
        }

        #endregion

        #region Public Methods

        /// <inheritdoc />
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            return Instance;
        }

        #endregion
    }

<RadioButton IsChecked="{Binding Path=SelectedMode,
                                                 Converter={viewModels:EnumComparisonConverter},
                                                 ConverterParameter={x:Static viewModels:PaintingMode.Terrain},
                                                 Mode=TwoWay}" />

public class EnumComparisonConverter : IValueConverter
{
    #region IValueConverter Implementation

    /// <inheritdoc />
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value?.Equals(parameter);
    }

    /// <inheritdoc />
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value?.Equals(true) == true ? parameter : Binding.DoNothing;
    }

    #endregion
}

<Grid>
  <Grid.Resources>
    <viewModels:EnumComparisonConverter x:Key="enumComparisonConverter"/>
  </Grid.Resources>
  <RadioButton IsChecked="{Binding Path=SelectedMode,
    Converter={StaticResource enumComparisonConverter},
    ConverterParameter={x:Static viewModels:PaintingMode.Terrain},
    Mode=TwoWay}" />
</Grid>