title: Silverlight 3 Checkbox Listbox bug when scrolling?
body: <p>I've spent a few minutes searching on Google and have not found anything related to this issue I'm having:</p>
  
  <p>Today I upgraded to the Silverlight 3 SDK and converted a project that I'm working on. I then noticed a bug in my program with a Listbox that has a Checkbox as its DataTemplate. </p>
  
  <p>When one or more items is checked, and I scroll up and down, it seems that a few of the Checkboxes at the extremes get checked off and on randomly. This does not trigger the Checked/Unchecked event, however. </p>
  
  <p>Has anyone seen this behavior? I'm not doing anything out of the ordinary, simply scrolling up and down once at least one checkbox has been checked, and a couple of others that I have not touched seem to get checked on and off repeatedly. This was definitely not happening with the Silverlight 2 SDK. </p>
  
  <p>Here's the XAML definition for my Listbox:</p>
  
  <pre><code>&lt;ListBox x:Name="cBoxSalesmen" Width="135" Height="200" 
   HorizontalAlignment="Left" VerticalAlignment="Top"&gt;
  &lt;ListBox.Template&gt;
      &lt;ControlTemplate&gt;
          &lt;Border Style="{StaticResource BorderStyleThin}"&gt;
              &lt;StackPanel Orientation="Vertical"&gt;
                  &lt;TextBlock Text="Salesmen" /&gt;
                  &lt;ScrollViewer Height="176" VerticalScrollBarVisibility="Visible" &gt;
                      &lt;ItemsPresenter /&gt;
                  &lt;/ScrollViewer&gt;
              &lt;/StackPanel&gt;
          &lt;/Border&gt;
      &lt;/ControlTemplate&gt;
  &lt;/ListBox.Template&gt;
  &lt;ListBox.ItemTemplate&gt;
      &lt;DataTemplate&gt;
          &lt;CheckBox Margin="0" Content="{Binding}" FontSize="10" HorizontalAlignment="Left"
                Checked="SalesmenCheckbox_Checked" Unchecked="SalesmenCheckbox_Unchecked"/&gt;
      &lt;/DataTemplate&gt;
  &lt;/ListBox.ItemTemplate&gt;
  &lt;/ListBox&gt;
  </code></pre>