title: Why doesn't the contentpresenter fill the grid cell?
body: <p>Ok I have a contentpresenter inside a grid cell:</p>
  
  <pre><code>        &lt;Grid&gt;
              &lt;Grid.RowDefinitions&gt;
                  &lt;RowDefinition Height="Auto"&gt;&lt;/RowDefinition&gt;
                  &lt;RowDefinition&gt;&lt;/RowDefinition&gt;
              &lt;/Grid.RowDefinitions&gt;
  
              &lt;Grid.ColumnDefinitions&gt;
                  &lt;ColumnDefinition&gt;&lt;/ColumnDefinition&gt;
              &lt;/Grid.ColumnDefinitions&gt;
  
              &lt;WrapPanel Grid.Row="0" Grid.Column="0"&gt;
                  &lt;RadioButton GroupName="a" IsChecked="{Binding Path=SpecifyRatedValues, Mode=TwoWay}"&gt;Specify&lt;/RadioButton&gt;
                  &lt;RadioButton GroupName="b" IsChecked="{Binding Path=SpecifyRatedValues, Converter={StaticResource invertBoolean}}"&gt;Auto generate&lt;/RadioButton&gt;
              &lt;/WrapPanel&gt;
  
              &lt;Border BorderBrush="Black" BorderThickness="3" Grid.Row="1" Grid.Column="0"&gt;
                  &lt;ContentPresenter Content="{Binding Path=RatedValues}"&gt;&lt;/ContentPresenter&gt;
              &lt;/Border&gt;                    
          &lt;/Grid&gt;
  </code></pre>
  
  <p>The contentpresenter finds which UI element to use by the datatemplate defined under resources:</p>
  
  <pre><code>    &lt;DataTemplate DataType="{x:Type ViewModels:RatedValuesViewModel}"&gt;
          &lt;Views:RatedValuesView /&gt;
      &lt;/DataTemplate&gt;
  </code></pre>
  
  <p>Now, everything works as expected, except for one thing: the View which is placed inside the contentpresenter at runtime does not expand to fill the entire cell. It leaves a big margin on the left and right side.</p>
  
  <p><b>How can I make the view inside the contentpresenter fill the entire available area?</b></p>