An item with the same key has already been added.

at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
at Infragistics.Collections.CollectionBase`1.AddItemSilently(Int32 index, T item)
at Infragistics.Collections.BindableItemCollection`1.AddBoundItem(Int32 index, T item)
at Infragistics.Collections.BindableItemCollection`1.GetItem(Int32 index)
at Infragistics.Collections.CollectionBase`1.get_Item(Int32 index)
at Infragistics.Controls.Menus.NodesManager.ResolveNodeForIndex(Int32 index)
at Infragistics.Controls.Menus.InternalNodesCollection.GetNodeForIndex(Int32 index, NodesManager currentManager, Int32 currentOffset, Int32 additionalOffset)
at Infragistics.Controls.Menus.InternalNodesCollection.GetNodeForIndex(Int32 index, NodesManager currentManager, Int32 currentOffset, Int32 additionalOffset)
at Infragistics.Controls.Menus.InternalNodesCollection.GetItem(Int32 index)
at Infragistics.Collections.CollectionBase`1.get_Item(Int32 index)
at Infragistics.Controls.Menus.Primitives.NodesPanel.MeasureOverride(Size availableSize)
at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
at System.Windows.UIElement.Measure(Size availableSize)
at System.Windows.ContextLayoutManager.UpdateLayout()
at System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
at System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()
at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)