title: WPF: Style based on another one in a separate assembly
body: <p>Assembly A - ResourceDictionary contains StyleA style. <br>
  Assembly B - ResourceDictionary.MergedDictionaries to merge resources from Assembly A into B.<p></p>
  
  <p>I would like to create a style in Assembly B "based on" StyleA. Is it possible? <br></p>
  
  <p>I am trying to create this style:</p>
  
  <pre><code>&lt;Style x:Key="StyleB" BasedOn="{StaticResource StyleA}"&gt;
     &lt;Setter Property="Button.Foreground" Value="Khaki"/&gt;
  &lt;/Style&gt;
  </code></pre>
  
  <p>But I get a XamlParseException exception at run-time, if I use StyleB:<br></p>
  
  <p><strong><em>Cannot convert the value in attribute 'Style' to object of type 'System.Windows.Style'. Can only base on a Style with target type that is base type 'IFrameworkInputElement'.  Error at object 'System.Windows.Controls.Button' in markup file 'SamSeekApp;component/mainwindow.xaml'</em></strong></p>