title: Attachable property not found in generic type
body: <p>I have a generic class <code>GridViewItemDragDrop&lt;T&gt;</code> in which a DependencyProperty is RegisterAttached:</p>
  
  <pre><code>namespace MobileAccess.ProjectExplorer.Library.Model.DragDrop
  {
      public class GridViewItemDragDrop&lt;T&gt; where T : class
      {
          public static readonly DependencyProperty IsEnabledProperty =
              DependencyProperty.RegisterAttached("IsEnabled",
                                                  typeof(bool),
                                                  typeof(GridViewItemDragDrop&lt;T&gt;),
                                                  new PropertyMetadata(new PropertyChangedCallback(OnIsEnabledPropertyChanged)));
  </code></pre>
  
  <p>Now, when I want to instantiate this property from within a GridView like the following:</p>
  
  <pre><code>&lt;UserControl x:Class="MobileAccess.ProjectExplorer.Library.Controls.WorkItemGridView"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
               xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
               xmlns:local="clr-namespace:MobileAccess.ProjectExplorer.Library.Controls"
               xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
               xmlns:area="clr-namespace:MobileAccess.ProjectExplorer.Model.Area;assembly=MobileAccess.ProjectExplorer.Model"             
               xmlns:system="clr-namespace:System;assembly=mscorlib"
               xmlns:aggregates="clr-namespace:MobileAccess.ProjectExplorer.Library.Aggregates"
               xmlns:dragdrop="clr-namespace:MobileAccess.ProjectExplorer.Library.Model.DragDrop"&gt;
  
  &lt;telerik:RadGridView x:Name="grvWorkItemItems" AllowDrop="True" dragdrop:GridViewItemDragDrop.IsEnabled="True"
                       d:DataContext="{d:DesignInstance Type=area:WorkItemViewItem}"&gt;
  </code></pre>
  
  <p>I get this in the error list:</p>
  
  <blockquote>
    <p>The attachable property 'IsEnabled' was not found in type 'GridViewItemDragDrop'.</p>
  </blockquote>
  
  <p>and get this in the build output</p>
  
  <blockquote>
    <p>The property 'GridViewItemDragDrop.IsEnabled' does not exist in XML namespace 'clr-namespace:MobileAccess.ProjectExplorer.Library.Model.DragDrop'</p>
  </blockquote>
  
  <p>I have a feeling that this has something to do with the class being a generic class. I can't seem to find a way to make it work. A little help is much appreciated.</p>