Cannot add columns to DataGrid

Dear Team,
I am implementing a master/detail hierarchy where the master's template is another datagrid with data gathered by a custom method. I want the detail data grid to show some properties in columns. However I cannot add any columns to the datagrid, if I click on add nothing happens. This beaviour occurs on any newly added datagrid btw.

Is there a bug introduced by a recent update?

Thank you for your support.

What is your application framework? Angular or Blazor?

I am using Angular Framework

I've placed a child DataGrid in the Template of a master DataGrid and I was able to add columns to the child grid:

I can do that too when I choose a data source method because all clumns are generated automatically and I can add or remove them as I wish. However this does not work when I pull an empty datagrid from th side bar and try to add columns immediately after that. The click on "Add" in the columns overview simply does nothng