Minor cleanup of directories

src/directories.cc

@@ -396,7 +396,7 @@ void Directories::select(const boost::filesystem::path &select_path) {
 }
 
 bool Directories::on_button_press_event(GdkEventButton* event) {
-  if(event->type==GDK_BUTTON_PRESS && event->button==3) {
+  if(event->type==GDK_BUTTON_PRESS && event->button==GDK_BUTTON_SECONDARY) {
     Gtk::TreeModel::Path path;
     if(get_path_at_pos(static_cast<int>(event->x), static_cast<int>(event->y), path)) {
       menu_popup_row_path=get_model()->get_iter(path)->get_value(column_record.path);