title: PropertyChanged member of INotifyPropertyChanged always null
body: <p>I have a class as follows</p>
  
  <pre><code>public partial class Configuration : INotifyPropertyChanged
  {
      private bool _isToolTips;
      public bool IsToolTips
      {
          get { return _isToolTips; }
          set { Set(this, "IsToolTips", ref _isToolTips, value, PropertyChanged); }
      }
  
      #region INotifyPropertyChanged functionality
  
      public static void Set&lt;T&gt;(object owner, string propName, ref T oldValue, T newValue,
          PropertyChangedEventHandler eventHandler)
      {
          // make sure the property name really exists
          if (owner.GetType().GetProperty(propName) == null)
          {
              throw new ArgumentException("No property named ‘" +
                  propName + "‘ on " + owner.GetType().FullName);
          }
  
          // we only raise an event if the value has changed
          if (Equals(oldValue, newValue)) return;
          oldValue = newValue;
          if (eventHandler != null)
          {
              eventHandler(owner, new PropertyChangedEventArgs(propName));
          }
      }
      public event PropertyChangedEventHandler PropertyChanged;
      private void notifyPropertyChanged(String info)
      {
          if (PropertyChanged != null)
          {
              PropertyChanged(this, new PropertyChangedEventArgs(info));
          }
      }
  
      #endregion INotifyPropertyChanged functionality
  }
  </code></pre>
  
  <p>This class is compiled in a separate assembly. I then add it to my MainWindow constructor as follows [edit]</p>
  
  <pre><code>    public MainWindow()
      {
          initializeAttributes();
          InitializeComponent();
          CurrentConfig = new Configuration
          {
              IsToolTips = true
          };
          DataContext = CurrentConfig;
          composeModules();
      }
  </code></pre>
  
  <p>[end edit]
  and in my XMAL I have this [edit]</p>
  
  <pre><code>&lt;MenuItem Name="ToolTips"
      Header="Tool Tips"
      IsCheckable="True"
      IsChecked="{Binding Source=CurrentConfig,
                          Path=IsToolTips,
                          Mode=TwoWay}"
      Click="onToolTipsClick"&gt;
  &lt;/MenuItem&gt;
  </code></pre>
  
  <p>[end edit]
  The problem is that the "PropertyChanged" member of my Configuration class is always set to null. Where am I going wrong?</p>