I put it under the scrollview in this way
and then bind the radHtmlPlaceholder_About to one htm page. The content can be displayed, but only occupies small portion of the whole screen, could I make it strecth to whole screen. I did not found the Vertical/HorzontalContentAlignment property in RadHtmlPlaceHolder control
<Grid x:Name="LayoutRoot">
<ScrollViewer x:Name="PageScrollViewer" Style="{StaticResource PageScrollViewerStyle}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" >
<telerik:RadHtmlPlaceholder Name="radHtmlPlaceholder_About" Width="Auto" Height="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
</ScrollViewer>
</Grid>
and then bind the radHtmlPlaceholder_About to one htm page. The content can be displayed, but only occupies small portion of the whole screen, could I make it strecth to whole screen. I did not found the Vertical/HorzontalContentAlignment property in RadHtmlPlaceHolder control