TreeTable Group Adding New Item

Lets assume we have a grouped treetable like https://snippet.webix.com/84fc967a

I can add an item to existing group like below kinda ugly but it’s okay.

$$('grida').add([{}], -1 , "0$1994")

• As I see the code above adds an item but the item data doesnt show up. It looks undefined

And I want to add a new record for a year 2018 which is not grouped before.

How can I create a new group for year 2018 without ungrouping.

Please check: https://snippet.webix.com/ngkksyq1

As I see the code above adds an item but the item data doesnt show up. It looks undefined

Template (which handles the data representation) tries to render the value of the precise data field ( title ). Without this field, it returns undefined.
Also, column template of the initial treetable adds common.treetable only for the groups (detected by $group field), while any branch can be detected by $count > 0.