code: function () {
        var select, data, r, maxR, c;
  
        if (selection.isMultiple()) {
          select = priv.selectionBorder.corners;
        }
        else {
          select = priv.currentBorder.corners;
        }
  
        autofill.fillBorder.disappear();
  
        data = datamap.getAll();
        rows : for (r = select.BR.row + 1; r < self.rowCount; r++) {
          for (c = select.TL.col; c <= select.BR.col; c++) {
            if (data[r][c]) {
              break rows;
            }
          }
          if (!!data[r][select.TL.col - 1] || !!data[r][select.BR.col + 1]) {
            maxR = r;
          }
        }
        if (maxR) {
          autofill.showBorder(self.view.getCellAtCoords({row: maxR, col: select.BR.col}));
          autofill.apply();
        }
      }
docs: Selects cells down to the last row in the left column, then fills down to that cell