code: private IPaletteItem[] getPaletteItems(String category){
  		List<IPaletteItem> list = items.get(category);
  		if(list==null){
  			return new IPaletteItem[0];
  		}
  		return list.toArray(new IPaletteItem[list.size()]);
  	}
docs: Returns PaletteItems which are contained by the specified category.
  
  @param category the category
  @return the array of items which are contained by the category