code: function isModifierKey(oEvent) {
  			var iKeyCode = oEvent.which; // jQuery oEvent.which normalizes oEvent.keyCode and oEvent.charCode
  
  			return (iKeyCode === KeyCodes.SHIFT) ||
  				(iKeyCode === KeyCodes.CONTROL) ||
  				(iKeyCode === KeyCodes.ALT) ||
  				(iKeyCode === KeyCodes.CAPS_LOCK) ||
  				(iKeyCode === KeyCodes.NUM_LOCK);
  		}
docs: legacy case where Event.key is not use, e.g. when jQuery.Events are created manually instead of using the Browser's KeyBoardEvent 
  Detect whether the pressed key is a modifier.
  
  Modifier keys are considered:
  SHIFT, CONTROL, ALT, CAPS_LOCK, NUM_LOCK
  These keys don't send characters, but modify the characters sent by other keys.
  
  @param {jQuery.Event} oEvent The event object of the <code>keydown</code>, <code>keyup</code> or <code>keypress</code> events.
  @static
  @returns {boolean} True if a modifier key was pressed