code: public int findInsertIdxByDivider(JQMListDivider d) {
          if (d == null) return -1;
          int i = findDividerIdx(d);
          if (i == -1) return -1;
          List<JQMListItem> lst = getItems();
          int rslt = i + 1;
          while (rslt < lst.size()) {
              if (lst.get(rslt) == null) { // next divider
                  return rslt;
              }
              rslt++;
          }
          return rslt;
      }
docs: For given divider finds the index at which new item should be inserted to become a part of
  this divider's group.
  
  @return - proper index for new item insertion, or -1 in case of error