renders external pages in an IFrame
positioned above the Silverlight plugin and therefore all styles applied on the page where the plugin is hosted affect the way the IFrame
is rendered. This is the reason why, we have little control over the way any external pages are displayed inside the HtmlPlaceholder
And you can control the ScrollBars
visibility/functionality mostly through styles. On our side the above suggestions worked as expected, although we will keep looking into other solutions to your scenario. However, it would be best if you check the style applied to the page where you add the Silverlight WebPart hosting the HtmlPlaceholder
control and manage the overflow properties accordingly to the page's content and your requirements.
the Telerik team