private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (isDirty)
            {
                MessageBoxResult result =
                    MessageBox.Show("Do you want to save your project?", "Project has Changed!", MessageBoxButton.YesNo, MessageBoxImage.Question);

                if (result == MessageBoxResult.Yes)
                {
                    Save_Click(sender, null);
                }
            }

            var userPrefs = new UserPreferences();

            userPrefs.WindowHeight = this.Height;
            userPrefs.WindowWidth  = this.Width;
            userPrefs.WindowTop    = this.Top;
            userPrefs.WindowLeft   = this.Left;
            userPrefs.WindowState  = this.WindowState;

            userPrefs.Save();
        }