Fixing wrong style override

Author: batzen

Fluent.Ribbon/Themes/Controls/RibbonScrollViewer.xaml

@@ -287,6 +287,7 @@
     <Style x:Key="Fluent.Ribbon.Styles.ScrollViewer"
            TargetType="{x:Type ScrollViewer}">
         <Setter Property="Focusable" Value="False" />
+        <Setter Property="OverridesDefaultStyle" Value="True" />
 
         <Setter Property="Fluent:ScrollViewerAttachedProperties.ScrollBarStyle" Value="{DynamicResource Fluent.Ribbon.Styles.ScrollBarWhite}" />
         <Setter Property="Template" Value="{DynamicResource Fluent.Ribbon.Templates.ScrollViewer}" />