I'm having exactly this same problem, but I'm not setting DataContext at all (it's inherited). 

If I remove the binding on Visiblity it goes away, here's a partial stack:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Element is already the child of another element.
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)        
   at MS.Internal.XcpImports.Collection_AddValue[T](PresentationFrameworkCollection`1 collection  CValue value)       
   at MS.Internal.XcpImports.Collection_AddDependencyObject[T](PresentationFrameworkCollection`1 collection  DependencyObject value)       
   at System.Windows.PresentationFrameworkCollection`1.AddDependencyObject(DependencyObject value)        
   at System.Windows.Controls.UIElementCollection.AddInternal(UIElement value)        
   at System.Windows.PresentationFrameworkCollection`1.Add(T value)        
   at Infragistics.Controls.Lists.XamTileView.OnItemPropertyChanged(Object sender  PropertyChangedEventArgs e)       
   at Infragistics.Controls.Lists.TilePaneCollection.Item_PropertyChanged(Object sender  PropertyChangedEventArgs e)       
   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender  PropertyChangedEventArgs e)       
   at Infragistics.Controls.Lists.TilePane.OnPropertyChanged(String propertyName)        
   at Infragistics.Controls.Lists.TilePane.OnTilePaneVisibilityChanged(DependencyObject target  DependencyPropertyChangedEventArgs e)       

Hi Petar,

I appologize for the late response, but I am on Holiday at the moment. Anyway, the suggested answer solves the problem.

Thx,

Ingo