Expander Header

   
 
<Window x:Class="SimpleStyles.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="SimpleStyles"
  Background="#F8F8F8">
  <ScrollViewer>
    <WrapPanel>
      <HeaderedItemsControl Header="Expander">
        <StackPanel Orientation="Horizontal">
          <Expander Width="200" Margin="8"  Header="This is the Header">
            <Border Height="100" />
          </Expander>
        </StackPanel>
      </HeaderedItemsControl>
   
    </WrapPanel>
  </ScrollViewer>
</Window>