C-Sharp CmdLet und WPF-UserControl.Visibility funktioniert nicht

<UserControl x:Class="NameSpace.ClassName"  
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"   
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"   
             xmlns:local="clr-namespace:NameSpace"  
             xmlns:external="clr-namespace:NameSpace"  
             mc:Ignorable="d"   
             Background="White"  
             Width="600"  
             BorderBrush="{Binding Path=BorderBrush_Notification, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"  
             BorderThickness="{Binding Path=BorderThickness_Notification, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"  
             Height="{Binding Path=Height_Notification, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"   
             Visibility="{Binding Path=Visibility_Notification, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"  
             IsEnabled="{Binding Path=Enebility_Notification, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"  
             d:DesignHeight="450" d:DesignWidth="800">  
...
...
/>

private static Visibility _Visibility_Notification = Visibility.Hidden;
public static Visibility Visibility_Notification
{
    get { return _Visibility_Notification; }
    set { _Visibility_Notification = value; ChangeProperty_STATIC(); }
}

ClassName.Visibility_Notification = System.WindowsVisibility.Visible;