GANTT Filter with Grouoping problem

Gantt
#1

If i had group the gantt with the group function and then i filter the gantt with onBeforeTaskDisplay
the all group Disappear

#2

Hello Gianfilippo,
Unfortunately, I couldn’t reproduce the issue:
http://snippet.dhtmlx.com/5/4400c098d

Probably, the issue is related to Gantt configuration, but it is hard to suggest what might be wrong as I don’t see your code.

Please, reproduce the issue in the snippet, then click on the “Share” button and send me the link:
https://snippet.dhtmlx.com/38ee1b370
Or send me an HTML file with all the necessary Javascript and CSS files.