expansor WPF vertical
<StackPanel x:Name="RightPanel">
<Expander x:Name="ExportExpander" ExpandDirection="Right">
<StackPanel Orientation="Horizontal">
<TextBlock Name="x" Text="Element One"/> <!--Textblock has Text property-->
<Button Name="y" Content="Element Two"/>
</StackPanel>
</Expander>
</StackPanel>
Sore Stork