Resources performance in gantt

We start using resources in gantt, but for larger projects it performance is very poor. Event after the data loaded, scroll is lagging and not working as smooth as in gantt chart.
As you can see on screen, my scroll is on bottom bot resources diagram is not scrolling.

FYI: We use custom cell template for resources.

Hello Wolland,
I tried to reproduce that issue in the official sample, but in my case, it works correctly:

It can help you if you enable the static_background config.

If you can reproduce the issue in the sample, please send me a screenshot with the parameters you used.
If you cannot reproduce it there, most likely, the issue is related to the Gantt configuration, but it is hard to suggest what might be wrong as I don’t se your code.
In that case, please add your configuration to the following snippet and make sure that the issue is reproduced there:

Then, click on the Save button and send me the link.
Or send me a ready demo with all the necessary JavaScript and CSS files so that I can reproduce the issue locally.