Adornments can be associated with a particular element in the adorned part -- that is the value of AdornedElement.

Adornments can be distinguished by their Part.Category. This property can be an arbitrary string value determined by the code creating the adornment, typically a tool that wants to be able to tell various adornments apart from each other. Use the Part method Part.GetAdornment to find an adornment for a part of a given category.

For example, adornments created by Part.UpdateSelectionAdornment have the Part.Category of "Selection". Those created by Northwoods.GoXam.Tool.ResizingTool.UpdateAdornments have a category of "Resize".

Adornments are always unbound parts -- but if the AdornedPart is bound to data, the adornment's data bindings can refer to the same data.

There cannot be any links connected to an adornment, nor can an adornment have members or be a member of a group.

An adornment cannot have its own adornments.

The template you use for a selection adornment will normally consist of either a Path (Silverlight) or SelectionHandle (WPF), or for nodes a SpotPanel, which is treated specially within an Adornment, or for links a LinkPanel. Although this element is normally the root Part.VisualElement, if it is surrounded by a panel or container or decorator, you need to make sure that it is the Node.LocationElement for the Adornment by naming it and supplying that name as the Node.LocationElementName.

The template you use for a tool adornment will normally consist of either a Path (Silverlight) or ToolHandle (WPF), or for nodes a SpotPanel containing Paths (Silverlight) or ToolHandles (WPF), or for links a LinkPanel containing Paths (Silverlight) or ToolHandles (WPF).

System.Object
   System.Windows.DependencyObject
      System.Windows.UIElement
         System.Windows.FrameworkElement
            System.Windows.Controls.ContentPresenter
               Northwoods.GoXam.Part
                  Northwoods.GoXam.Node
                     Northwoods.GoXam.Adornment

Reference