title: gridrow that has visibility set to collapsed, still reserves a black spots
body: <p>I am trying to place an ad grid for my panorama view. </p>
  
  <p>The problem is that when i'm trying to hide the ad grid by setting the visibility to collapsed(when the app isn't 'trial'), i can't see the ad anymore but i see a reserved black space the size of the ad. Here is my code:</p>
  
  <pre><code>    &lt;phone:PhoneApplicationPage xmlns:my1="clr-namespace:Google.AdMob.Ads.WindowsPhone7.WPF;assembly=Google.AdMob.Ads.WindowsPhone7"  xmlns:my="clr-namespace:adMob7;assembly=adMob7"  
      x:Class="WP7SQLiteClient._MainPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
      xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
      xmlns:controls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:local="clr-namespace:WP7SQLiteClient"
      mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="696"
      FontFamily="{StaticResource PhoneFontFamilyNormal}"
      FontSize="{StaticResource PhoneFontSizeNormal}"
      Foreground="{StaticResource PhoneForegroundBrush}"
      SupportedOrientations="Portrait"  Orientation="Portrait"
      shell:SystemTray.IsVisible="True"&gt;
      &lt;phone:PhoneApplicationPage.Resources&gt;
  
      &lt;/phone:PhoneApplicationPage.Resources&gt;
          &lt;!--LayoutRoot is the root grid where all page content is placed--&gt;
      &lt;Grid x:Name="LayoutRoot" Background="Transparent"&gt;
          &lt;!--Pivot Control--&gt;
          &lt;Grid.RowDefinitions&gt;
              &lt;RowDefinition Height="*"/&gt;
              &lt;RowDefinition Height="Auto"/&gt;
          &lt;/Grid.RowDefinitions&gt;
  
          &lt;controls:Panorama Grid.Row="0" x:Name="panoramaMain" SelectionChanged="Panorama_SelectionChanged"&gt;
              &lt;controls:PanoramaItem Header="messages"&gt;
  
  
              &lt;/controls:PanoramaItem&gt;
              &lt;controls:PanoramaItem Header="share"&gt;
  
              &lt;/controls:PanoramaItem&gt;
          &lt;/controls:Panorama&gt;
  
        &lt;Grid Grid.Row="1" Background="Yellow" x:Name="grid" Margin="0" Visibility="Collapsed" &gt;
      &lt;adduplex:AdControl x:Name="ad" Margin="0" xmlns:adduplex="clr-namespace:AdDuplex;assembly=AdDuplex.AdControl.Silverlight"
                          AppId="7671" 
                          /&gt;
          &lt;/Grid&gt;
      &lt;/Grid&gt;
  
  
  &lt;/phone:PhoneApplicationPage&gt;
  </code></pre>
  
  <p>How can i hide or remove the ad without having the black space reserved?</p>