+bool
+ArdourDropdown::on_scroll_event (GdkEventScroll* ev)
+{
+ using namespace Menu_Helpers;
+
+ if (_scrolling_disabled) {
+ return false;
+ }
+
+ const MenuItem * current_active = _menu.get_active();
+ const MenuList& items = _menu.items ();
+ int c = 0;
+
+ if (!current_active) {
+ return true;
+ }
+
+ /* work around another gtkmm API clusterfuck
+ * const MenuItem* get_active () const
+ * void set_active (guint index)
+ *
+ * also MenuList.activate_item does not actually
+ * set it as active in the menu.
+ *
+ */
+
+ switch (ev->direction) {
+ case GDK_SCROLL_UP:
+
+ for (MenuList::const_reverse_iterator i = items.rbegin(); i != items.rend(); ++i, ++c) {
+ if ( &(*i) != current_active) {
+ continue;
+ }
+ if (++i != items.rend()) {
+ c = items.size() - 2 - c;
+ assert(c >= 0);
+ _menu.set_active(c);
+ _menu.activate_item(*i);
+ }
+ break;
+ }
+ break;
+ case GDK_SCROLL_DOWN:
+ for (MenuList::const_iterator i = items.begin(); i != items.end(); ++i, ++c) {
+ if ( &(*i) != current_active) {
+ continue;
+ }
+ if (++i != items.end()) {
+ assert(c + 1 < (int) items.size());
+ _menu.set_active(c + 1);
+ _menu.activate_item(*i);
+ }
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ return true;
+}