title: Building StackPanel inside StackPanel with GridView component
body: <p>I need to build something like a StackPanel Horizontal inside a StackPanel Vertical that contains many buttons of variable width (but summarized width is fixed).</p>
  
  <p>I did it on my own and it worked very well indeed... but when I try to reply the result with the GridView page generated by VS2012 GroupedView it sucks.</p>
  
  <pre><code>&lt;GridView
      x:Name="itemGridView"
      AutomationProperties.AutomationId="ItemGridView"
      AutomationProperties.Name="Grouped Items"
      Grid.RowSpan="2"
      Padding="116,137,40,46"
      ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"
      ItemTemplate="{StaticResource PalinsestoTemplate}"
      SelectionMode="None"
      IsSwipeEnabled="False"
      IsItemClickEnabled="True"
      ItemClick="ItemView_ItemClick"&gt;
  
      &lt;GridView.ItemsPanel&gt;
          &lt;ItemsPanelTemplate&gt;                        
              &lt;VirtualizingStackPanel Orientation="Vertical" IsHitTestVisible="False"/&gt;
          &lt;/ItemsPanelTemplate&gt;
      &lt;/GridView.ItemsPanel&gt;
      &lt;GridView.GroupStyle&gt;
          &lt;GroupStyle&gt;
              &lt;GroupStyle.HeaderTemplate&gt;
                  &lt;DataTemplate&gt;
                      &lt;Grid Margin="10,5,0,0"&gt;
                          &lt;Button
                              AutomationProperties.Name="Group Title"
                              Click="Header_Click"
                              Style="{StaticResource TextPrimaryButtonStyle}" &gt;
                              &lt;StackPanel Orientation="Horizontal"&gt;
                                  &lt;TextBlock Text="{Binding Nome}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" /&gt;
                                  &lt;TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-7,0,10" Style="{StaticResource GroupHeaderTextStyle}"/&gt;
                              &lt;/StackPanel&gt;
                          &lt;/Button&gt;
                      &lt;/Grid&gt;
                  &lt;/DataTemplate&gt;
              &lt;/GroupStyle.HeaderTemplate&gt;
              &lt;GroupStyle.Panel&gt;
                  &lt;ItemsPanelTemplate&gt;
                      &lt;StackPanel Orientation="Horizontal" Margin="0,0,80,0" IsHitTestVisible="False" /&gt;
                  &lt;/ItemsPanelTemplate&gt;
              &lt;/GroupStyle.Panel&gt;
          &lt;/GroupStyle&gt;
      &lt;/GridView.GroupStyle&gt;
  &lt;/GridView&gt;
  </code></pre>
  
  <p>Above is my code, but the problem is that the <code>minimum hitTest area</code> for each item inside will break the fixed summarized width. How can I resolve this?</p>