Enum dependency property never updates from the view - wpf

Question

I have a dependency property on a usercontrol that is an enum. I bind to it and set it in the main window view but it does not change.
This is the usercontrol and the icon is the enum
<local:GoogleMaterialIcon Icon="AccountBalance"/>
Here is the enum
public enum Icon
{
_3DRotation,
Accessibility
};
here is the dp
/// <summary>
/// Dependency Property used to back the <see cref="Icon"/> Property
/// </summary>
public static readonly DependencyProperty IconProperty =
DependencyProperty.Register("Icon",
typeof(Icon),
typeof(GoogleMaterialIcon),
new PropertyMetadata(null));
and finally the property
public Icon Icon
{
get { return (Icon)GetValue(IconProperty); }
set
{
SetValue(IconProperty, value);
}
}
I place a breakpoint inside the set icon but it never runs. also the enum is in its own file. every time i run it shows me the wrong icon because the dp reverts to the first enum and never updates
update: full code of the usercontrol behind
public partial class GoogleMaterialIcon : UserControl
{
/// <summary>
/// Dependency Property used to back the <see cref="Icon"/> Property
/// </summary>
public static readonly DependencyProperty IconProperty =
DependencyProperty.Register("Icon",
typeof(Icon),
typeof(GoogleMaterialIcon),
new PropertyMetadata(null));
/// <summary>
/// Constructor
/// </summary>
public GoogleMaterialIcon()
{
InitializeComponent();
}
/// <summary>
/// Select a predefined icon to use
/// </summary>
public Icon Icon
{
get { return (Icon)GetValue(IconProperty); }
set
{
SetValue(IconProperty, value);
}
}
}

Answer 1

Obviosly under some - at least for me - strange circumstances, even Microsoft only comes up with an solution rather than an explanation.
In your PropertyMetadata you are missing the PropertyChanged-Event
Unfortunately i cannot explain in deep, whats happening here. But using the PropertyChanged-Event of the DependencyProperty seems for me an acceptable workaround.