verticalscrollbarvisibili

Why does VerticalScrollBarVisibility not work in a style in Silverlight?

VerticalScrollBarVisibility works when I define it inline like this: <UserControl x:Class="TestScrollBar.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas....