How can I group the columns of pivot table?

How can I group the columns of pivot table ?

https://snippet.webix.com/p4p1iu30

When pivot table was render at first time the first column still show 2 columns.

How can I solve this issue.

Hello @Mhoo ,
I can confirm the issue, thank you for the report! This looks like a regression, and will be fixed in the next release. Unfortunately, there is no fully-fledged workaround for the time being, as some of the related logic is private and cannot be modified.