There is a control that can achieve this kind a behavior have you tried a Popup control?
Check this out
Here's an examp;e"
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ToggleButton x:Name="MainButton" Content="Show popup" VerticalAlignment="Top" HorizontalAlignment="Right"/>
<Popup PlacementTarget="{Binding ElementName=MainButton}" Placement="Bottom" AllowsTransparency="True" IsOpen="{Binding ElementName=MainButton, Path=IsChecked}">
<Grid>
<Border BorderBrush="Orange" BorderThickness="1" Background="Yellow"/>
<TextBlock Text="Lorem Ipsum is simply dummy text of the printing and typesetting industry"/>
</Grid>
</Popup>
</Grid>