Webpage should not be accessible till popup is closed/submit

Hi, I used the following code to open the popup on in a silverlight  XAML page, but i can access the web page other links when the pop up is open, the webpage should not be accessible till the popup is closed , could any one please say hot to achieve it.
My XAML code is :  ( and i am open popup by setting popMessage.IsOpen=true in xaml.cs )












Height="200" Padding="10,10,10,10" CornerRadius="25,25,25,25"
Grid.Column="1" Grid.Row="1">









Text="Message Goes Here" FontFamily="Trebuchet MS" FontSize="24"
HorizontalAlignment="Center" VerticalAlignment="Center"
Foreground="#7FFFFFFF" TextWrapping="Wrap" TextAlignment="Center" />