title: WPF Label binding via Tag to multiple ComboBoxes
body: <p>Normally I associate Labels with TextBoxes/ComboBoxes on a one-to-one basis so I can decorate the label when the ComboBox has focus ... something like this</p>
  
  <pre><code>&lt;Label
      Grid.Row="1"
      Grid.Column="1"
      Style="{StaticResource styleLabelTextBlockLeft}"
      Tag="{Binding ElementName=cboColor, Path=(IsFocused)}"
  &gt;
      &lt;TextBlock
          TextWrapping="Wrap"&gt;What is your favorite color? 
      &lt;/TextBlock&gt;
  &lt;/Label&gt;
  &lt;ComboBox
      x:Name="cboColor"
      Grid.Row="1"
      Grid.Column="3"
      ...
  /&gt;
  </code></pre>
  
  <p>What I would like to do is highlight the Label if <em>either</em> the ComboBox to the immediate right of the Label has focus OR the second ComboBox to the right of the first ComboBox has focus (all on the same row).  Pseudocode follows:</p>
  
  <pre><code>&lt;Label
      Grid.Row="1"
      Grid.Column="1"
      Style="{StaticResource styleLabelTextBlockLeft}"
      Tag="{Binding ElementName=cboColorOne, Path=(IsFocused)}"
      Tag="{Binding ElementName=cboColorTwo, Path=(IsFocused)}"
  &gt;
      &lt;TextBlock
          TextWrapping="Wrap"&gt;What is your favorite color? 
      &lt;/TextBlock&gt;
  &lt;/Label&gt;
  &lt;ComboBox
      x:Name="cboColorOne"
      Grid.Row="1"
      Grid.Column="3"
      ...
  /&gt;
  &lt;ComboBox
      x:Name="cboColorTwo"
      Grid.Row="1"
      Grid.Column="5"
      ...
  /&gt;
  </code></pre>
  
  <p>Any ideas?  Thanks.</p>