Fixed prefix lookup.

Author: gumme

src/AddIns/DisplayBindings/WpfDesign/WpfDesign.XamlDom/Project/XamlObject.cs

@@ -116,6 +116,12 @@ internal XmlAttribute XmlAttribute {
 		static XmlElement VirualAttachTo(XmlElement e, XmlElement target) 
 		{
 			var prefix = target.GetPrefixOfNamespace(e.NamespaceURI);
+			
+			if (String.IsNullOrEmpty(prefix) && target.OwnerDocument.DocumentElement != null)
+			{
+				prefix = target.OwnerDocument.DocumentElement.GetPrefixOfNamespace(e.NamespaceURI);
+			}
+			
 			XmlElement newElement = e.OwnerDocument.CreateElement(prefix, e.LocalName, e.NamespaceURI);
 
 			foreach (XmlAttribute a in target.Attributes) {