I want to change the Icon of a ToggleButton (Content of [Fluent RibbonBar](http://fluent.codeplex.com/)) Depending on it's IsChecked Property. Now I have written the following style snippet:

```
<Fluent:ToggleButton.Style>
    <Style BasedOn="{StaticResource RibbonButtonStyle}" TargetType="{x:Type Fluent:ToggleButton}">
        <Setter Property="OverridesDefaultStyle" Value="True"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding  RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Fluent:ToggleButton}}, Path=IsChecked}" Value="False">
                <Setter Property="Icon" Value="{StaticResource ResourceKey=Style.Images.Pined}"/>
            </DataTrigger>
            <DataTrigger Binding="{Binding  RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Fluent:ToggleButton}}, Path=IsChecked}" Value="True">
                <Setter Property="Icon" Value="{StaticResource ResourceKey=Style.Images.Unpined}"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Fluent:ToggleButton.Style>

```

The problem is that the Trigger doesn't load the Image well. The problem is not, that IsChecked doesn't actualize itself, I've already tested this. And also I don't set the icon property anywhere else. The image resources also works fine if I use them otherwhere.

Information for Rebuild: I've put the ToggleButton into the Backstage as the DataTemplate of a RibbonListBox placed in a BackstageTabItem.