Unhandled exception when adding a RibbonGroup

I am trying to implement the Outlook Ribbon in a WPF application, and the ribbon works fine. However when I try to add a RibbonGroup, I get an unhandled exception in the XAML.

Here is my code:

<r:RibbonWindow 
    x:Class="WpfArticles.Main"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:r="clr-namespace:Microsoft.Windows.Controls.Ribbon;assembly=RibbonControlsLibrary"
    Title="Main" Height="500" Width="500">

    <StackPanel>
        <r:Ribbon Title="WPF Ribbon - Document1" x:Name="ribbon" >
            <r:RibbonTab Label="Home">
                <r:RibbonGroup Name="Test" />
            </r:RibbonTab>
            <r:RibbonTab Label="Insert"/>
            <r:RibbonTab Label="Help"/>
        </r:Ribbon >

and I am getting this error in the XAML :

Object reference not set to an instance of an object. at
Microsoft.Windows.Controls.Ribbon.RibbonGroup.OnApplyTemplate() at
System.Windows.FrameworkElement.ApplyTemplate() at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.StackPanel.Measure开发者_如何学JAVAOverride(Size constraint) at
Microsoft.Windows.Controls.Ribbon.RibbonGroupsContainer.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at
System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Border.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at
System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Control.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Control.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.StackPanel.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at
System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Decorator.MeasureOverride(Size constraint) at
System.Windows.Documents.AdornerDecorator.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Border.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Border.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.DockPanel.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Border.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Control.MeasureOverride(Size constraint) at
MS.Internal.WindowControl.DesignTimeWindow.MeasureOverride(Size availableSize) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Designer.SimpleViewManager.DesignerBackground.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Decorator.MeasureOverride(Size constraint) at
Microsoft.Windows.Design.Interaction.DesignerView.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Designer.Viewport.MeasureOverride(Size availableSize) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at
System.Windows.Controls.ScrollContentPresenter.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.ScrollViewer.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Grid.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint) at
System.Windows.Controls.ContentPresenter.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Controls.Control.MeasureOverride(Size constraint) at
System.Windows.FrameworkElement.MeasureCore(Size availableSize) at
System.Windows.UIElement.Measure(Size availableSize) at
System.Windows.Interop.HwndSource.SetLayoutSize() at
System.Windows.Interop.HwndSource.set_RootVisualInternal(Visual value) at
System.Windows.Interop.HwndSource.set_RootVisual(Visual value) at
MS.Internal.Designer.VSIsolatedDesigner.ViewHolder.Initialize() at
MS.Internal.Designer.VSIsolatedDesigner.ViewHolder..ctor(UIElement content) at
MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.get_ViewHandle() at
MS.Internal.Host.Isolation.IsolatedView.get_ViewHandle() at
MS.Internal.Designer.DesignerPane.LoadDesignerView()

What am I doing wrong? Without the <r:RibbonGroup Name="Test" /> it works fine!

Thanks for your help and time

I suspect you are using an older version, as the Label property is no longer valid. The latest version can be found here.

I downloaded that ribbon but could not add the reference for some reason. Anyway, I downloaded an example and it clearly said that the Group will throw an exception if it is empty. So now everything works fine. Thanks for your help!