code: function isModifierKey(oEvent) {
  			var sKey = oEvent.key; // based on KeyBoardEvent.key (https://www.w3.org/TR/uievents/) and (https://www.w3.org/TR/uievents-key/)
  			return (sKey === 'Shift') ||
  				(sKey === 'Control') ||
  				(sKey === 'Alt') || // Chrome uses 'Alt' and 'AltGraph, IE only use 'Alt'
  				(sKey === 'AltGraph') || // see above -^
  				(sKey === 'CapsLock') ||
  				(sKey === 'NumLock');
  		}
docs: Detect whether the pressed key is a modifier.
  
  Modifier keys are considered:
  SHIFT, CONTROL, ALT, ALTGRAPH, 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