In the current version of RadGanttView control there isn't a built-in filtering feature that could be used to filter the columns in the grid part of the control because the implementation of such functionality might be scenario specific and we believe that implementing a general approach for it is out of the scope of the control.
You can check our SDK example that demonstrate how to implement sorting in the grid portion of the control by creating attached properties. Our online SDK repository
is available here
and the corresponding example is listed as GanttView/GridSorting
. The approach on achieving filtering in the GanttView control is similar to the one in the sorting example.
Hope this is helpful.
the Telerik team