title: WPF DataGrid horizontal scrollbar not showing
body: <p>I have created simple DataGrid with 4 columns, which go outside the bounds of DataGrid, and horizontal scrollbar is not showing. I tried setting width to each column but nothing changed. Here is my XAML:</p>
  
  <pre><code>&lt;Window x:Class="WPFTest.Window1"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          Title="Window1" Height="300" Width="300"&gt;
      &lt;Grid&gt;
          &lt;DataGrid Height="200" Width="200" HorizontalScrollBarVisibility="Visible"&gt;
              &lt;DataGrid.Columns&gt;
                  &lt;DataGridTextColumn Header="Column 1" /&gt;
                  &lt;DataGridTextColumn Header="Column 2" /&gt;
                  &lt;DataGridTextColumn Header="Column 3" /&gt;
                  &lt;DataGridTextColumn Header="Column 4" /&gt;
              &lt;/DataGrid.Columns&gt;
          &lt;/DataGrid&gt;
      &lt;/Grid&gt;
  &lt;/Window&gt;
  </code></pre>
  
  <p>And here is what I get:</p>
  
  <p><img src="https://i.stack.imgur.com/wpo1G.png" alt="enter image description here"></p>
  
  <p>I have also tried wrapping DataGrid with ScrollViewer. Nothing. How can I make scrollbar appear?</p>