Trying to integrate charts, got this run time error Widgetset does not cont

I’m getting this run time error when I am trying to use charts:
Widgetset does not contain implementation for ru.bazon.vaadin.ganttdiagram.canvas.GanttDiagramCanvas. Check its component connector’s @Connect mapping, widgetsets GWT module description file and re-compile your widgetset. In case you have downloaded a vaadin add-on package, you might want to refer to add-on instructions

Do you have a Client-Side widgetset specified in your web.xml? If yes, did you recompile it after downloading the Add-On?

Btw. This question was asked a million times already. If you’re typing vaadin widgetset does not contain… into google you should get a bunch of suggestions and also, this exception is not add-on specific so even a solution for the Refresher Add-On, for example, can solve your problem.

Thank you