code: function(cellIndex) {
          var cell = this.cells[cellIndex],
              cellDate = this.cellDates[cellIndex],
              cellDateIndex = this._indexOfSelectedFieldArray(cellDate);
  
          var selectable = Dom.hasClass(cell, this.Style.CSS_CELL_SELECTABLE);
          if (!selectable) { this.logger.log("The cell at cellIndex:" + cellIndex + " is not a selectable/deselectable cell", "info"); }
  
          if (selectable) {
  
              this.beforeDeselectEvent.fire();
  
              var selected = this.cfg.getProperty(DEF_CFG.SELECTED.key),
                  dCellDate = this._toDate(cellDate),
                  selectDate = cellDate.concat();
  
              if (cellDateIndex > -1) {
                  if (this.cfg.getProperty(DEF_CFG.PAGEDATE.key).getMonth() == dCellDate.getMonth() &&
                      this.cfg.getProperty(DEF_CFG.PAGEDATE.key).getFullYear() == dCellDate.getFullYear()) {
                      Dom.removeClass(cell, this.Style.CSS_CELL_SELECTED);
                  }
                  selected.splice(cellDateIndex, 1);
              }
  
              if (this.parent) {
                  this.parent.cfg.setProperty(DEF_CFG.SELECTED.key, selected);
              } else {
                  this.cfg.setProperty(DEF_CFG.SELECTED.key, selected);
              }
  
              this.deselectEvent.fire([selectDate]);
          }
  
          return this.getSelectedDates();
      }
docs: Deselects a date on the current calendar by referencing the index of the cell that should be deselected.
  This method is used to easily deselect a single cell (usually with a mouse click) without having to do
  a full render. The selected style is removed from the cell directly.
  
  If the cell is not marked with the CSS_CELL_SELECTABLE class (as is the case by default for out of month
  or out of bounds cells), the method will not attempt to deselect it and in such a case, beforeDeselect and
  deselect events will not be fired.
  
  @method deselectCell
  @param {Number} cellIndex The index of the cell to deselect in the current calendar.
  @return {Date[]} Array of JavaScript Date objects representing all individual dates that are currently selected.