Gantt chart task tooltips are not working


I work at a company, which are testing DHTMLX Gantt Chart product. We are very interested and want to buy a PRO license, but the tooltips are not working.

What do we need to allow tooltips in Gantt chart?

We imported the tolltips extension

import "dhtmlx-gantt/codebase/ext/dhtmlxgantt_tooltip.js";

And set tooltip template

gantt.templates.tooltip_text = (start, end, task) => { return `<b>Procedure:</b> ${task.text}<br/><b>Start time:</b> ${task.start}<br/><b>End time:</b> ${task.end}`; };

But tooltips are not showed when mouse is over the task. No error message, but it does not work.

Is there something more we have to do?

Thanks a lot.

Tooltips should work with any version, including standard version. But you need to make sure that Gantt and the extension that you connect have the same version. For example, for Gantt Standard 5.1.2 you need to connect tooltip extension with Standard 5.1.2 version:
Here is the snippet showing how it works:
I suspect that you use Angular2+ or React, so maybe you need to add additional code. Please send me the package with all files so I can reproduce it locally and see what might be wrong.