LegendItem.invalidate Method
        
 Ensures the legend is re-drawn using the current settings at the next best 
 time made available by the browser. This method is normally called automatically when
 needed.
 
         
        Parameters
        
            - remeasure
            
 
            - 
                
Type: Boolean
(optional) False if only appearance settings were changed; 
 otherwise changes in data are handled and re-measured.
 
Optional: True