title: IsEnabled binding to a boolean
body: <p>I have a list a simple dialog box which contains a few checkboxes, I wanted to have an Ok button that would be disabled unless the user changed a setting. In my view I have an OkEnabled property that I was binding the isEnabled property of the button to, if a check box changes its value it sets OkEnabled to true, but for some reason this doesnt enable the button.</p>
  
  <pre><code>public bool OkEnabled
  {
      get
      {
          return m_okEnabled;
      }
      set
      {
          m_okEnabled = value;
          OnPropertyChanged("OkEnabled");
      }
  }
  </code></pre>
  
  
  
  <pre><code>&lt;Button Content="OK" Style="{StaticResource MyButton}" Height="23" 
          HorizontalAlignment="Left" Margin="20" Name="m_okbutton" 
          VerticalAlignment="Top" Width="75"
          Click="okClick" IsEnabled="{Binding Path=OkEnabled}"/&gt;
  </code></pre>
  
  <p>For some reason the Ok button won't change state when the OkEnabled property changes state. If I bind the IsEnabled property to one of the checkboxes I can see the button change state as the check box changes.</p>