The RadGantt offers WAI-ARIA support and it is enabled by default for the control.
In order to use WAI-ARIA the form element on the page must have a role attribute set to "application" (
<form id="form1" runat="server" role="application">). For more information on this requirement see: W3C: WAI-ARIA
An issue with the use of WAI-ARIA is that using ARIA attributes results in invalid HTML mark-up. When you run a HTML document containing ARIA attributes through the W3C Validator it shows errors in the results for any ARIA attributes. The reason is that the DOCTYPE declarations do not include any information about the WAI ARIA attributes and you cannot have a valid document which includes elements, attributes, and attribute values, not detailed in its DTD’s.