// must do shortcuts first or the scrollbar will get them...
  if (event == FL_ENTER || event == FL_LEAVE) return 1;
  if (event == FL_KEYBOARD && type() >= FL_HOLD_BROWSER) {
    void* l1 = selection_;
    void* l = l1; if (!l) l = top_; if (!l) l = item_first();
    if (l) {
      if (type()==FL_HOLD_BROWSER) {
        switch (Fl::event_key()) {
        case FL_Down:
      while ((l = item_next(l))) {
        if (item_height(l)>0) {select_only(l, when()); break;}
      }
      return 1;
        case FL_Up:
          while ((l = item_prev(l))) {
        if (item_height(l)>0) {
          select_only(l, when());
          break; // no need to test wp (return 1)
        }
      }
          return 1;
        }
      } else  {
        switch (Fl::event_key()) {
        case FL_Enter:
        case FL_KP_Enter:
          select_only(l, when() & ~FL_WHEN_ENTER_KEY);
      if (wp.deleted()) return 1;
      if (when() & FL_WHEN_ENTER_KEY) {
        set_changed();
        do_callback();
      }

The line "if (event == FL_ENTER || event == FL_LEAVE) return 1;

prohibits the execution of the later do_callback when FL_WHEN_ENTER_KEY

This prevents using the FL_Enter key in a user callback.

David