I need a special widgetset to use this addon?? i asking because when i star

I need a special widgetset to use this addon??
i asking because when i start the app show this message
Widgetset ‘com-vaadin.DefaultWidgetSet’ does not contain an
implemetation for org.titv.gantt.Gantt. Checkt the connectors @Connect
mapping,…
17657101.png

Hi Adrian, have you got solution for that. Same issue i am facing. Can you please help me in this.

Thanks in Advance