... tried below but wrappanel is not available, where does that come from?
<Grid.Resources>
<Style x:Key="alternateRowStyle" TargetType="gridView:GridViewRow" >
<Setter Property="Background" Value="#F7F3F7" />
</Style>
<Style x:Key="primaryRowStyle" TargetType="gridView:GridViewRow" >
<Setter Property="Background" Value="#CECFD6" />
</Style>
<Style TargetType="{x:Type gridViewGridViewGroupPanel}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type telerik:GridViewGroupPanel}">
<Grid Background="Transparent">
<Border HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Opacity="0.6" />
<Border HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
<WrapPanel: Margin="-2,0,0,0">
<ItemsPresenter x:Name="itemsPresenter" Margin="0,10,10,0" />
</WrapPanel>
<TextBlock Text="Some text." Margin="10, 0, 0, 0" Foreground="#7F000000" IsHitTestVisible="False" VerticalAlignment="Center" Visibility="{TemplateBinding HasItems, Converter={StaticResource invertedBooleanConverter}}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Grid.Resources>
