Problem with 4.2.1 update


i just updated my version to the 4.2.1 update, because i need the autoscroll feature.
As soon as i updated the version, i tried some basic gantt functionalities.

But when i drag a task horizontally and then drop, i receive this error in javascript console:
dhtmlxgantt.js:10977 Uncaught TypeError:[(“add_” + n)] is not a function
at Object.add (dhtmlxgantt.js:10977)
at Object.calculateEndDate (dhtmlxgantt.js:5989)
at Object.calculateEndDate (dhtmlxgantt.js:6273)
at Object.gantt.calculateEndDate (dhtmlxgantt.js:6760)
at Object._fix_dnd_scale_time (dhtmlxgantt.js:2649)
at Object.on_mouse_up (dhtmlxgantt.js:2676)
at Object. (dhtmlxgantt.js:2425)

Can anyone help me please?

Thank you


We need to reproduce the issue to have the opportunity understand the cause of the problem.
Could you please provide with access to your application/ create a demo where the problem can be reproduced here - Gantt 4.2.1 is used / or at least show your code which possibly causes the problem?

I have the same problem when I update the finish date or start date of a task.

When it does the initial load, it doesn’t give any error.


Hello Abel,
Probably, it is related to the Gantt configuration, but it is hard to suggest what might be wrong as I don’t see your code.
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.
Or send me a ready demo with all the necessary Javascript and CSS files so that I can reproduce the issue locally.