Silverlight DataPager control loses first/last buttons

I'm using the DataPager control in XAML as follows:

     <Grid.ColumnDefinitions>
      <ColumnDefinition Width="1*" />
      <ColumnDefinition Width="1*" />
      <ColumnDefinition Width="1*" />
     </Grid.ColumnDefinitions>

    <data:DataPager Grid.Column="1"
       Source="{Binding PagedCollection, ElementName=开发者_JAVA技巧ucPagingControl}"
       PageSize="{Binding PagedCollection.PageSize, ElementName=ucPagingControl}" 
       AutoEllipsis="True" 
       DisplayMode="FirstLastPreviousNextNumeric" />

and all displays well for the first 99 pages

However, after page 100 I lose the first/last button graphics

Any ideas why or how to change the number of pages displayed to recover the space?

Turns out the fix was in the Grid definition. The following works:

     <Grid.ColumnDefinitions>
      <ColumnDefinition />
      <ColumnDefinition Width="Auto" />
      <ColumnDefinition />
     </Grid.ColumnDefinitions>