wpf toolbar bug: ToolBar.Overflowmode does not work in binding scenarios

This works (places the button in the overflow area):

    <ToolBar>
        <Button ToolBar.OverflowMode="Always">Hit me</Button>
    </ToolBar>

This does not (does not place/keep the button in the overflow area):

    <开发者_开发知识库;ToolBar Grid.Row="3" ItemsSource="{Binding Path=Groups[0].Items}"></ToolBar>

    <DataTemplate DataType="{x:Type local:ItemViewModel}">
        <Button ToolBar.OverflowMode="Always">Hit me</Button>
    </DataTemplate>

Does anyone know if there is a workaround for this problem?

I found a way of applying overflow to all items, and using a custom style selector, you can probably tailor the overflow to only refer to the items relevant for you.

Static version:

    <Style x:Key="itemContainerStyle">
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=Description}" Value="Foo">
                <Setter Property="ToolBar.OverflowMode" Value="Always"></Setter>
            </DataTrigger>
        </Style.Triggers>
    </Style>

    <Style TargetType="ToolBar">
        <Setter Property="ItemContainerStyle" Value="{StaticResource itemContainerStyle}"></Setter>
    </Style>