<StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="LabelSimple.Pane1"> <DockPanel Margin="30,10,3,3" Grid.Column="0" Grid.Row="2"> <!--<Snippet1>--> <TextBox Name="tb" Width="50"/> <Label Target="{Binding ElementName=tb}">_File (Press Alt to see the underline)</Label> <!--</Snippet1>--> </DockPanel> </StackPanel>