I had a Invalid Cross Thread access issue, but a little research and I managed to fix it by using the Dispatcher.

Now in my app I have objects with lazy loading. I'd make an Async call using WCF and as usual I use the Dispatcher to update my objects DataContext, however it didn't work for this scenario. I did however find a solution here. Here's what I don't understand.

In my UserControl I have code to call an Toggle method on my object. The call to this method is within a Dispatcher like so.

Dispatcher.BeginInvoke( () => _CurrentPin.ToggleInfoPanel() );

As I mentioned before this was not enough to satisfy Silverlight. I had to make another Dispatcher call within my object. My object is NOT a UIElement, but a simple class that handles all its own loading/saving.

So the problem was fixed by calling

Deployment.Current.Dispatcher.BeginInvoke( () => dataContext.Detail = detail );

within my class.

Why did I have to call the Dispatcher twice to achieve this? Shouldn't a high-level call be enough? Is there a difference between the Deployment.Current.Dispatcher and the Dispatcher in a UIElement?