public static CustomButtonBuilder NavButton(this GridBuilder builder, string caption, string buttonIcon = null)
        {
            var buttonBuilder = new CustomButtonBuilder(builder.CurrentGrid)
            {
                Current = {Caption = caption}
            };

            if (!string.IsNullOrWhiteSpace(buttonIcon))
            {
                buttonBuilder.Current.ButtonIcon = buttonIcon;
            }

            return buttonBuilder;
        }
        public static GridBuilder ButtonSeparator(this GridBuilder builder, string caption = null, string sepClass = null)
        {
            var buttonBuilder = new CustomButtonBuilder(builder.CurrentGrid)
            {
                Current = {IsSeparator = true}
            };

            if (!string.IsNullOrWhiteSpace(sepClass))
            {
                buttonBuilder.Current.ButtonIcon = sepClass;
            }
            if (caption != null)
            {
                buttonBuilder.Current.Caption = caption;
            }

            return builder;
        }