Similar to what we have in other controls, when there is are no records, we should have a specific template where we can show an image or some text that shows that the Gantt chart could not be displayed since there is no data.

Attached is a sample implementation which can be used as a temporary workaround. To run the project, place the .NET 4.5 version of the Telerik.Web.UI.dll in the bin folder of the project.