How to add a gantt control menu

I have read the dhtmlx documentation for gantt but unable to find how to add this kind of menu in the attached
picture. This will be really very helpful for me if someone assist me. Thanks in advance.

Hello Sohel,
This menu is not part of Gantt, it is just a menu that was created with the HTML elements and some styling.

You can check the separate example and its source code here:

And I have that demo in the snippet:

Thank you for your kind support.:blush: