title: WPF Custom ItemsControl - Wrapping issue
body: <p>I want to create a breadcrumb control that has a button at the beginning that will clear the breadcrumb items. My problem is getting that first button to wrap properly with the rest of the items. Here's my style:</p>
  
  <pre><code>&lt;Style TargetType="{x:Type local:Breadcrumb}"&gt;
      &lt;Setter Property="ItemTemplate"&gt;
          &lt;Setter.Value&gt;
              &lt;DataTemplate&gt;
                  &lt;Button Content="{Binding}"
                          FontSize="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbFontSize}" 
                          FontFamily="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbFont}"
                          FontWeight="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbFontWeight}"
                          Width="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbItemWidth}"
                          Height="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbItemHeight}"
                          Margin="0,0,-22,10"
                          Style="{DynamicResource BreadcrumbButton}" /&gt;
              &lt;/DataTemplate&gt;
          &lt;/Setter.Value&gt;
      &lt;/Setter&gt;
  
      &lt;Setter Property="ItemsPanel"&gt;
          &lt;Setter.Value&gt;
              &lt;ItemsPanelTemplate&gt;
                  &lt;WrapPanel /&gt;
              &lt;/ItemsPanelTemplate&gt;
          &lt;/Setter.Value&gt;
      &lt;/Setter&gt;
  
      &lt;Setter Property="Template"&gt;
          &lt;Setter.Value&gt;
              &lt;ControlTemplate TargetType="{x:Type ItemsControl}"&gt;
                  &lt;WrapPanel&gt;
                      &lt;Button Content="Menu" Height="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbItemHeight}"
                              Width="{Binding RelativeSource={RelativeSource AncestorType=local:Breadcrumb}, Path=BreadcrumbItemWidth}"/&gt;
                      &lt;ItemsPresenter Height="{TemplateBinding Height}" Width="{TemplateBinding Width}" /&gt;
                  &lt;/WrapPanel&gt; 
              &lt;/ControlTemplate&gt;
          &lt;/Setter.Value&gt;
      &lt;/Setter&gt;
  &lt;/Style&gt;
  </code></pre>
  
  <p>When all of the items fit on the same line it displays properly:</p>
  
  <p><img src="https://i.stack.imgur.com/ZbzOu.png" alt="enter image description here"></p>
  
  <p>When it starts to wrap, it pushes all of the items below the "Menu" button:</p>
  
  <p><img src="https://i.stack.imgur.com/gkwDI.png" alt="enter image description here"></p>
  
  <p>Is there a way that I can update this so that the other elements do not go below the Menu button?</p>