How can I add nav tab inside lightbox sections

Gantt
#1

I am trying to add a navtab inside lightbox.

please suggest me.

#2

Hello Subhasis,
You can show any HTML element in the lightbox by displaying it as a custom lightbox element:
https://docs.dhtmlx.com/gantt/desktop__custom_editor.html
Here is an example:
http://snippet.dhtmlx.com/522d0f19e