I have defined a dependency property, LightColor, as follows:

public Brush LightColor
{
    get { return (Brush)GetValue(LightColorProperty); }
    set { SetValue(LightColorProperty, value); }
}
public static readonly DependencyProperty LightColorProperty = DependencyProperty.Register("LightColor", typeof(Brush), typeof(TheView), new PropertyMetadata(ColorChangedCallback));

I am trying to change the color of the Brush using:

(LightColor as SolidColorBrush).Color = Colors.Green; 

This should trigger the ColorChangedCallback but it doesn't. I can see that the Color property is set, but the callback is never called.
Is this expected behaviour or a bug? Trying the same with WPF triggers ColorChangedCallback.
Thank you.