Dependency Properties - What's the point of having 2 owners?
If you look at `Selector` and `TabItem` classes they apparently both own the `IsSelectedProperty`.

    static Selector()
    {
        ...
        IsSelectedProperty = DependencyProperty.RegisterAttached("IsSelected", typeof(bool), typeof(Selector), ...);
        ...
    }
    
    static TabItem()
    {
        IsSelectedProperty = Selector.IsSelectedProperty.AddOwner(typeof(TabItem), ...);
        ...
    }

So I guess my question is... since the Tabitem contains the actual propertychanged logic, what is the point of the IsSelectedProperty even residing in the `Selector` class?
Dependency Properties - What's the point of having 2 owners?
===

If you look at `Selector` and `TabItem` classes they apparently both own the `IsSelectedProperty`.

    static Selector()
    {
        ...
        IsSelectedProperty = DependencyProperty.RegisterAttached("IsSelected", typeof(bool), typeof(Selector), ...);
        ...
    }
    
    static TabItem()
    {
        IsSelectedProperty = Selector.IsSelectedProperty.AddOwner(typeof(TabItem), ...);
        ...
    }

So I guess my question is... since the Tabitem contains the actual propertychanged logic, what is the point of the IsSelectedProperty even residing in the `Selector` class?