button inside header of telerik rad expander is not working on first click?

[sri hari]

I am getting issue with telerik rad expander which contains button inside header. it is working as usual when i expand or collapse but after clicking button inside header, it is not expanding or collapsing for 1st time and it is expanding or collapsing on 2nd click of radexpander. I am using version VS2010 + silverlight 4 + telerik contorls Q1 2012 . I am not getting why it is behaving when i click on button inside rad expander header and can any one try this attached code snippet which i tried and tell me how to resolve this issue?

 <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel >
        <telerik:RadExpander IsExpanded="False"   Style="{StaticResource RadExpanderStyle}" >
            <telerik:RadExpander.Header>
                <StackPanel  Height="35" VerticalAlignment="Bottom" Orientation="Horizontal">
                    <Button x:Name="btnView" Click="btnView_Click"   Content="View" HorizontalAlignment="Left" VerticalAlignment="Center" Width="70" Style="{StaticResource ButtonStyle}" Margin="0,0,10,0"/>
                    <Button x:Name="btnPrint" Click="btnPrint_Click"  Content="Print" HorizontalAlignment="Left" VerticalAlignment="Center" Width="70" Style="{StaticResource ButtonStyle}" Margin="0,0,10,0"/>
                </StackPanel>
            </telerik:RadExpander.Header>
            <TextBlock Text="welcomeeeeeeeeeeeeeeeee............." FontSize="18"/>
        </telerik:RadExpander>
        </StackPanel>
    </Grid>