Binding StringFormat giving incorrect result

For some reason using Content="{Binding Time, StringFormat=t} is still giving me a long date. The backing field is a DateTime property initialised with DateTime.Now but no matter what string format I try it still shows the full date...

I would like only to see HH:mm tt

Any ideas?

XAML :

<Window x:Class="ArgosSystem.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:loc="clr-namespace:ArgosSystem" xmlns:sys="clr-namespace:System;assembly=System" Title="MainWindow" Height="800" Width="1280" Loaded="Window_Loaded"> <Window.Resources> <DataTemplate DataType="{x:Type loc:Picknote}"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="200" MinWidth="200" /> <ColumnDefinition Width="350" /> <ColumnDefinition Width="250" /> <ColumnDefinition Width="50" /> </Grid.ColumnDefinitions> <Label Content="{Binding Time, StringFormat=t}" VerticalContentAlignment="Center" Foreground="IndianRed" FontSize="36" Grid.Column="0" /> <Label Content="{Binding Customer}" VerticalContentAlignment="Center" Foreground="IndianRed" FontSize="36" Grid.Column="1" /> <Label Content="{Binding PicknoteNo}" VerticalContentAlignment="Center" Foreground="IndianRed" FontSize="36" Grid.Column="2" /> <Label Content="{Binding Qty}" VerticalContentAlignment="Center" Foreground="IndianRed" FontSize="36" Grid.Column="3" /> </Grid> </DataTemplate> </Window.Resources> <Grid Background="Black"> <DockPanel> <ScrollViewer Name="lstPicknoteScroll" VerticalScrollBarVisibility="Auto"> <ItemsControl Name="lstPicknotes" ItemsSource="{Binding}" IsTabStop="False" Foreground="Cornsilk" /> </ScrollViewer> </DockPanel> </Grid> </Window> 

C# :

public partial class MainWindow : Window { ObservableCollection<Picknote> picknotes = new ObservableCollection<Picknote>(); public MainWindow() { InitializeComponent(); lstPicknotes.DataContext = picknotes; } private void Window_Loaded(object sender, RoutedEventArgs e) { picknotes.Add(new Picknote { Time = DateTime.Now, Customer = "REED FOR SPEED", PicknoteNo = "PKN767677", Qty = 100 }); picknotes.Add(new Picknote { Time = DateTime.Now.AddHours(-2), Customer = "F1 AUTOMOTIVE", PicknoteNo = "PKN767677", Qty = 50 }); picknotes.Add(new Picknote { Time = DateTime.Now.AddHours(-1), Customer = "FERGUSENS", PicknoteNo = "PKN767677", Qty = 10 }); } }