ui/src/main/java/ucar/nc2/ui/widget/SuperComboBox.java
protected int getItemPos() {
      if (nitems < 1)
        return -arrow_size;   // dont show indicator
      else if (nitems == 1)
        return b.width/2;   // indicator in center

      int item = table.getSelectedRowIndex();  // selected item
      int eff_width = b.width - 2*arrow_size;   // effective width
      int pixel =  (item * eff_width)/(nitems-1);  // divided into n-1 intervals
      return pixel+arrow_size;
    }
protected int getItemPos() {
      if (nitems < 1)
        return -arrow_size;   // dont show indicator
      else if (nitems == 1)
        return b.width/2;   // indicator in center

      int item = table.getSelectedRowIndex();  // selected item
      int eff_width = b.width - 2*arrow_size;   // effective width
      int pixel =  (item * eff_width)/(nitems-1);  // divided into n-1 intervals
      return pixel+arrow_size;
    }
return slider indicator position for currently selected item