But I found that this would not happen to the official loading big datasets demo
That can happen if you have split tasks in the task rows. Gantt displays all split tasks on a task row even if they are outside the viewport.
Here is an example:
The horizontal scroll works smoothly there as the tasks are already rendered. But the vertical scroll requires Gantt to create HTML elements of the whole rows, and it causes the lag.
If you don’t have split tasks, you might have a different use case, but as I don’t see your code, it is hard to suggest what might be wrong. In that case, please, add your configuration in the following snippet and make sure that the issue is reproduced there:
Then, click on the
Share button and send me the link.