code: function StackItem(options, isNegative, x, stackOption) {
  			var stackItem = this;
  
  			// Tells if the stack is negative
  			stackItem.isNegative = isNegative;
  
  			// Save the options to be able to style the label
  			stackItem.options = options;
  
  			// Save the x value to be able to position the label later
  			stackItem.x = x;
  			
  			// Save the stack option on the series configuration object
  			stackItem.stack = stackOption;
  
  			// The align options and text align varies on whether the stack is negative and
  			// if the chart is inverted or not.
  			// First test the user supplied value, then use the dynamic.
  			stackItem.alignOptions = {
  				align: options.align || (inverted ? (isNegative ? 'left' : 'right') : 'center'),
  				verticalAlign: options.verticalAlign || (inverted ? 'middle' : (isNegative ? 'bottom' : 'top')),
  				y: pick(options.y, inverted ? 4 : (isNegative ? 14 : -6)),
  				x: pick(options.x, inverted ? (isNegative ? -6 : 6) : 0)
  			};
  
  			stackItem.textAlign = options.textAlign || (inverted ? (isNegative ? 'right' : 'left') : 'center');
  		}
docs: The class for stack items