Fix #2097: Prefix:PropertyName is invalid syntax

ILSpy.BamlDecompiler/Xaml/XamlProperty.cs

@@ -80,12 +80,13 @@ namespace ILSpy.BamlDecompiler.Xaml {
 			XName name;
 			if (!isFullName)
 				name = XmlConvert.EncodeLocalName(PropertyName);
-			else
+			else {
 				name = typeName.LocalName + "." + XmlConvert.EncodeLocalName(PropertyName);
 
-			if (parent == null || (parent.GetDefaultNamespace() != typeName.Namespace &&
-			                       parent.Name.Namespace != typeName.Namespace))
-				name = typeName.Namespace + name.LocalName;
+				if (parent == null || (parent.GetDefaultNamespace() != typeName.Namespace
+					                && parent.Name.Namespace != typeName.Namespace))
+					name = typeName.Namespace + name.LocalName;
+			}
 
 			return name;
 		}