在silverlight中改变面板的标题

我试图改变面板的标题在silverlight取决于什么用户点击。我为面板控件设置的是

<Silverlight_Controls:FloatingPanel 
        x:Name="pnlEntities" 
        Margin="0,0,0,20" 
        VerticalAlignment="Bottom" 
        HorizontalAlignment="left"
        Width="auto"
        Height="200"
        Title=""
        TitleColor="White"
        HorizontalContentAlignment="Stretch"
        VerticalContentAlignment="Stretch"
        WindowBackgroundBorder="DarkGray" 
        WindowBackground="DodgerBlue" 
        ContentBackgroundBorder="Transparent" 
        ContentBackground="WhiteSmoke"
        IsCloseButtonVisible="True" 
        IsDraggable="True" 
        IsHeightResizeable="True" 
        IsWidthResizeable="True" 
        IsHeaderVisible="True"
        ScrollViewer.VerticalScrollBarVisibility="Auto" 
        ScrollViewer.HorizontalScrollBarVisibility="Auto">
        <Data:DataGrid 
        </Data:DataGrid>

我有一个按钮，我确认它会触发，但它不会改变任何东西。我想我不明白是否有什么需要重新加载，或者如果updatelayout是错误的事情调用。

 private void buttInformation_ExecuteCompleted(object sender, IdentifyEventArgs e)
    {
            pnlEntities.Title = "AreaA";
            pnlEntities.UpdateLayout(); 
    }