title: WPF bug? Grid's column does not accommodate ListBox scrollbar
body: <p>In the following example, the leftmost column's width does not increase to accommodate the <code>ListBox</code>'s scrollbar that appears when the <code>UserControl</code>'s height is decreased:</p>
  
  <pre><code>&lt;UserControl
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      x:Class="Example"&gt;
      &lt;Grid&gt;
          &lt;Grid.ColumnDefinitions&gt;
              &lt;ColumnDefinition Width="Auto" /&gt;
              &lt;ColumnDefinition /&gt;
          &lt;/Grid.ColumnDefinitions&gt;
          &lt;Grid.RowDefinitions&gt;
              &lt;RowDefinition Height="Auto" /&gt;
              &lt;RowDefinition /&gt;
          &lt;/Grid.RowDefinitions&gt;
          &lt;TextBlock Grid.Row="0" Grid.ColumnSpan="2"&gt;Example text&lt;/TextBlock&gt;
          &lt;ListBox Grid.Row="1" Grid.Column="0"&gt;
              &lt;ListBoxItem&gt;One&lt;/ListBoxItem&gt;
              &lt;ListBoxItem&gt;Two&lt;/ListBoxItem&gt;
              &lt;ListBoxItem&gt;Three&lt;/ListBoxItem&gt;
              &lt;ListBoxItem&gt;Four&lt;/ListBoxItem&gt;
              &lt;ListBoxItem&gt;Five&lt;/ListBoxItem&gt;
          &lt;/ListBox&gt;
          &lt;Expander Grid.Row="1" Grid.Column="1" Header="Expander" /&gt;
      &lt;/Grid&gt;
  &lt;/UserControl&gt;
  </code></pre>
  
  <p>When the <code>TextBlock</code> with the <code>ColumnSpan</code> attribute is removed the column resizes as expected. Is this a bug in WPF?</p>