Outlook Email new message disables WPF window

This email applications works as expected, however when the new mail message is open, the WPF application window is disabled.  How can I enable the WPF application WHILE the email message window is open?

XAML

<Window x:Class="WpfApplication37.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="200" Width="300"><Grid><Button Content="Click to open Outlook" Name="button1" Click="button1_Click" Margin="61,45,73,78"  /></Grid></Window>

C#

using Outlook = Microsoft.Office.Interop.Outlook;  
namespace WpfApplication37
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {

            Outlook.Application objOutlook = new Outlook.Application();
            Outlook.MailItem mic = objOutlook.CreateItem(Outlook.OlItemType.olMailItem) as Outlook.MailItem;

            mic.To = "abc@gmail.com";
            mic.Subject = "This is the subject...";
            mic.Display(true);
        }
    }
}