public PaletteManager(SymbolPalette palette, IEnumerable <PaletteObj> items)
        {
            palette.SetImages(new Dictionary <string, Image>
            {
                { "box", Properties.Resources.Box },
                { "circle", Properties.Resources.Circle },
                { "empty", Properties.Resources.Empty }
            });

            foreach (var item in items)
            {
                palette.Add(item);
            }
        }