title: Difference between Attached and non-Attached Dependency Properties in Silverlight
body: <p>Okay Stackers, I've spent a good couple of hours on this question, and I want to know if anybody has a definitive answer.<br/>
  For all the research I've done, I can't find ANY difference between <code>.Register</code> and <code>.RegisterAttached</code> in <strong>Silverlight</strong>.  Now, before you jump the gun and tell me that <code>.RegisterAttached</code> is used for attaching a DP to another class, try implementing an Attached Dependency Property using <code>DependencyProperty.Register()</code>.  I have found not a single difference, and so I am at a loss as to what the difference is.<br/>
  Furthermore, in my specific case, I'm attempting to extend the functionality of the Grid class, and want to give it some extra properties.  As such, I've tried listing passing both <code>typeof(Grid)</code> and <code>typeof(FluidLayoutManager)</code> (the implementing class) as the ownerType parameter and it also seems to make very little difference...  (I believe it does make a difference when I pass two custom classes from the same namespace.  However when passing a Microsoft defined class vs. a custom class, I always have it showing up in the XAML as a DP of the custom class.)<br/>
  Any clarification on this topic would be much appreciated, as I'm sitting here scratching my head, and wondering if there is any difference at all, or if Microsoft is just screwing with me once again.</p>