<Application x:Class="Toolkit.Shell.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:properties="clr-namespace:Toolkit.Shell.Properties">
<TextBox Grid.Row="2" Grid.Column="3" Text="{Binding Source={StaticResource Settings}, Path=Default.SetPublisherHost}" />
and when the application closes
Shell.Properties.Settings.Default.Save();