title: Why XAML's Margin attribute has four components not two?
body: <p>When you see Margin attribute in a XAML file of WPF, it has four components. Why is this? The first two components make sense they are offset from top left window, but what is it for the third and fourth components when we have Width and Height?</p>
  
  <pre><code>&lt;Grid&gt;
          &lt;Button Content="Button" Height="27" HorizontalAlignment="Left" Margin="29,27,0,0" Name="clickButton" VerticalAlignment="Top" Width="86" Click="clickButton_Click" /&gt;
          &lt;TextBox Height="27" HorizontalAlignment="Left" Margin="29,90,0,0" Name="textBoxOut" VerticalAlignment="Top" Width="276" /&gt;
  &lt;/Grid&gt;
  </code></pre>