Click on devexpress gridControl's new row Item

Hi,

Desktop App developed in C# .NET Framework WPF. 
TestComplete version : Version: 15.52.2.7 x64
Script langugage: Javascript

I'm trying to access the new row item on a Devexpress (v21.2.4) GridControl. My goal is to populate all columns in the new row item before pressing enter to validate the input. I tried several ways to access the new row item. I used the ClickNewRowCell to access the desired column for edition but I get the following error at runtime:

Possible reasons:
1. The application stopped responding.
2. The application was compiled incorrectly (see the Open Applications topic in the help system).
3. An error occurred in TestComplete/TestExecute.

Technical information:
195 0x8007139f (The group or resource is not in the correct state to perform the requested operation.) Edit.

I also tried to edit the desired cell using the devexpress SetCellValue with the rowHandle of the new row item (which is -2147483647), but the row handle is not recognized...

For information: all testComplete methods with "NewRow" are not working here. The method 'TableView.AddNewRow(true)' is working and triggers the InitNewRow callback from my C# WPF code.

My question is the following:

How can I access and populate the cells of the new item row of my grid?

Can you please provide a Javascript code snippet ?

Thanks in advance!

BG