private void AddLanguageFile_OnClick(object sender, RoutedEventArgs e)
        {
            // Configure open file dialog box.
            OpenFileDialog dlg = new OpenFileDialog {
                DefaultExt = ".txt", Filter = "Language Files (.txt)|*.txt"
            };

            // Show open file dialog box.
            bool?result = dlg.ShowDialog();

            // Process open file dialog box results
            if (result != true)
            {
                return;
            }

            // Show language name dialog box.
            TextBoxWindow textboxDlg = new TextBoxWindow();

            result = textboxDlg.ShowDialog("Add Language", "Please enter the name of the language!");

            if (result != true)
            {
                return;
            }

            // Add language file to project.
            ProjectSettings projectSettings = (ProjectSettings)this.DataContext;
            LanguageFile    languageFile    = new LanguageFile {
                LanguageTag = textboxDlg.Text, Path = dlg.FileName
            };

            projectSettings.AddLanguageFile(languageFile);

            // Refresh list.
            this.LanguageFileList.Items.Refresh();
        }