<Window x:Class="Windows.TransparentBackground"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Windows" Height="300" Width="300"
    WindowStyle="None" AllowsTransparency="true"
    MouseLeftButtonDown="window_MouseLeftButtonDown"        
    >
  <Window.Background>    
    <ImageBrush ImageSource="shapes.png"></ImageBrush>
  </Window.Background>
    <Grid>
      <Grid.RowDefinitions>
        <RowDefinition></RowDefinition>
        <RowDefinition></RowDefinition>
        <RowDefinition></RowDefinition>
        <RowDefinition></RowDefinition>
      </Grid.RowDefinitions>
      <Button Margin="20">A Sample Button</Button>   
      <Button Margin="20" Grid.Row="2" Click="cmdClose_Click">Close</Button>   
    </Grid>
</Window>
