Hello,
When you use the template function, you can only return HTML elements.
That means you can only add the Javascript handlers.
If you want to show native Vue or React components and add the native handlers, you need to use the onrender method:
https://docs.dhtmlx.com/gantt/desktop__specifying_columns.html#modifyingcellsafterrendering
Here are the demos:
https://files.dhtmlx.com/30d/bcac2d270e7cf8f74f9271d74ffc489b/reactive-gantt+gantt-instance+react-components.zip