Tabbing Issue on DHTMLX 4.1 grid while Tabbing after click

In DHTMLX 4.1 version when we click on Grid columns and Tab after that it is not working as it should when we use keyboard arrow keys to go to next column in Grid.
Please suggest possible implementation for this scenario.

Unfortunately the tabbing on the header of the grid is not available. Please, try to tab through the cells of the grid.