Popups in wpf

Here is come code to show a popup in wpf, i've nothing in the popup at the moment, just a gradient background and border.

[code:c#]

Width="{Binding ElementName=bdrCalendar, Path=ActualWidth, Converter={StaticResource MarginValueConverter}}"
Height="150"
Placement="Center"
PopupAnimation="Scroll"
AllowsTransparency="True"
PlacementTarget="{Binding ElementName=bdrCalendar}"
MouseDown="popup1_MouseDown" >

[/code]