title: Wrapping items horizontally in a VariableSizedWrapGrid
body: <p>I have a GridView containing VariableSizedWrapGrid, like this...</p>
  
  <pre><code>    &lt;local:MyGridview    
          Padding="116,0,0,0"        
          x:Name="itemGridView"
          AutomationProperties.AutomationId="ItemGridView"
          AutomationProperties.Name="Grouped Items"
          Grid.Column="1"
          Grid.Row="1"
          SelectionMode="None"
          ItemTemplateSelector="{StaticResource templateSelector}"
          ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}" 
          IsItemClickEnabled="True"
          ItemClick="itemGridView_ItemClick"&gt;
  
          &lt;GridView.ItemsPanel&gt;
              &lt;ItemsPanelTemplate&gt;
                  &lt;VirtualizingStackPanel Orientation="Horizontal" Margin="0"/&gt;
              &lt;/ItemsPanelTemplate&gt;
          &lt;/GridView.ItemsPanel&gt;
  
          &lt;GridView.GroupStyle&gt;
              &lt;GroupStyle&gt;
                  &lt;GroupStyle.HeaderTemplate&gt;
                      &lt;DataTemplate&gt;
                          &lt;Grid&gt;
                              &lt;TextBlock Text="{Binding Key}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" /&gt;
                          &lt;/Grid&gt;
                      &lt;/DataTemplate&gt;
                  &lt;/GroupStyle.HeaderTemplate&gt;
                  &lt;GroupStyle.Panel&gt;
                      &lt;ItemsPanelTemplate&gt;
                          &lt;VariableSizedWrapGrid Orientation="Vertical" ItemWidth="1" ItemHeight="1" Margin="0,3,40,0" /&gt;
                      &lt;/ItemsPanelTemplate&gt;
                  &lt;/GroupStyle.Panel&gt;
              &lt;/GroupStyle&gt;
          &lt;/GridView.GroupStyle&gt;
  
      &lt;/local:MyGridview&gt;
  </code></pre>
  
  <p>Which displays items like this...</p>
  
  <p><img src="https://i.stack.imgur.com/YjdFZ.png" alt=""></p>
  
  <p>I want to make it stack items horizontally rather than vertically so that the orange tile sits next to the blue one rather than below it</p>
  
  <p>I've tried changing the Orientation of the VariableSizedWrapGrid to Horizontal but this happens....</p>
  
  <p><img src="https://i.stack.imgur.com/pJcpE.png" alt=""></p>
  
  <p>Am I doing something really silly?</p>