How to reset grid line height after using splitter?

Question

The next XAML hides the bottom line when you uncheck the box. Everything will be fine until you resize it with gridsplitter. Then checking / unchecking the box does nothing. Given that the converter sets the height to 0, I expected the line to hide. What's happening? How can I reset the heights after moving the separator?

<Grid>
    <Grid.Resources>
        <m:CheckedToLengthConverter x:Key="checkedToLengthConverter" />
    </Grid.Resources>
    <Grid.RowDefinitions>
        <RowDefinition Height="3*" />
        <RowDefinition Height="{Binding Mode=OneWay, ElementName=ShowBottomCheckBox, Path=IsChecked, Converter={StaticResource checkedToLengthConverter}, ConverterParameter=2}" />
    </Grid.RowDefinitions>
    <Border Background="Blue" />
    <CheckBox Name="ShowBottomCheckBox" IsChecked="True" />
    <GridSplitter HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Height="5" />
    <Border Background="Red" Grid.Row="1" />
</Grid>

Converter

public class CheckedToLengthConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if ((bool)value)
            return new GridLength(int.Parse(parameter.ToString()), GridUnitType.Star);

        return new GridLength(0, GridUnitType.Pixel);
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Answer 1

, , * . . , TwoWay, .

public class CheckedToLengthConverter : MarkupExtension, IValueConverter
{
    public GridLength TrueValue { get; set; }
    public GridLength FalseValue { get; set; }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return System.Convert.ToBoolean(value) ? TrueValue : FalseValue;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Binding.DoNothing;
    }

    #region Overrides of MarkupExtension

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    #endregion
}

<Grid>
    <Grid.Resources>
        <m:CheckedToLengthConverter TrueValue="2*" FalseValue="*" x:Key="c1" />
        <m:CheckedToLengthConverter TrueValue="3*" FalseValue="0" x:Key="c2" />
    </Grid.Resources>

    <Grid.RowDefinitions>
        <RowDefinition Height="{Binding Mode=TwoWay, Path=IsChecked, 
                       ElementName=ShowBottomCheckBox, 
                       Converter={StaticResource c1}}"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="{Binding Mode=TwoWay, Path=IsChecked, 
                       ElementName=ShowBottomCheckBox, 
                       Converter={StaticResource c2}}"/>
    </Grid.RowDefinitions>
    <Border Background="Blue" />
    <CheckBox Name="ShowBottomCheckBox" IsChecked="True" />
    <GridSplitter HorizontalAlignment="Stretch" 
                  Grid.Row="1" VerticalAlignment="Bottom" Height="5" 
                  ResizeBehavior="PreviousAndNext" />
    <Border Background="Red" Grid.Row="2" />
</Grid>

Answer 2

UX, . , , , Visual States ?