title: WPF Binding does not update Button-Content
body: <p>May someone tell me whats wrong with this sourcecode?
  when i click the button its not updating ist value?
  At first binding the converter makes his job.</p>
  
  <p>the sourcecode is pretty big so i will post only some snippets.</p>
  
  <p>XAML: 
  Instances is type of ObservableCollection
      
          
      </p>
  
  <pre><code>&lt;ListBox Name="Instances"&gt;
      &lt;ListBox.ItemTemplate&gt;
          &lt;DataTemplate&gt;
              &lt;Button Tag="{Binding Path=Instance.Name}" Content="{Binding Path=Instance.Active, Converter={StaticResource BTSC}}" Click="ChangeAccess"/&gt;
              &lt;TextBlock Text="{Binding Path=Instance.Name}"/&gt;
           &lt;/DataTemplate&gt;
      &lt;/ListBox.ItemTemplate&gt;
  &lt;/ListBox&gt;
  </code></pre>
  
  <p>Converter:</p>
  
  <pre><code>public class BoolToStringConverter : IValueConverter
  {
      public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
      {
          if (((Boolean)value) == true)
              return "No";
          else
              return "Yes";
      }
  
      public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
      {
          throw new NotImplementedException();
      }
  } 
  </code></pre>
  
  <p>Event:</p>
  
  <pre><code>private void ChangeAccess(object sender, RoutedEventArgs e)
  {
      for...
      if ((sender as Button).Tag.ToString() == (DP.Instances[i].Instance as CInstance).Name)
      {
          SkipIfAndElse...
          DP.Instances[i].Instance.Active = true;
      }
  }
  </code></pre>
  
  <p>CInstance:</p>
  
  <pre><code>class CInstance : INotifyPropertyChanged
  {
      private Boolean active;
      public Boolean Active
      {
          get { return active; }
          set
          {
              active = value;
              NotifyPropertyChanged("Access");
          }
      }
  }
  </code></pre>
  
  <p>All other values of the CInstance class are updating as expected. </p>