Hello @Z! Sorry for the delay!

Are you not getting errors on the page on load? Running your code here I can see the grid and all, but console points errors running layout. I don't need to do anything besides loading the page. I'm not sure this is supposed to be related to the issue but it could -- in potential -- be interfering in the call to code behind.

The end result on load is a grid with column bodies that do not match the width with the column headers'.

As the 'test' button effectively edits the record so that the issue is reproduced, are the drag-and-drop, editor, command column, renderer, all required in order to reproduce the issue? Quite confused here. Do you think you could trim down the example to the bare minimum required to reproduce the issue?