text:     <UserControl
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      x:Class="WPFAddIn1.AddInUI">
      
      <StackPanel>
  		<Button Click="clickMeButton_Click" Content="Click Me!" />
      </StackPanel>
      
  </UserControl>
  