How to change subforms in LibreOffice 5?

I don’t know how to edit subforms in LibreOffice 5. More exactly, the columns that are on a table. In the fourth version of LibreOffice I proceed as follows: 1. Forms 2. Right Button, edit 3. In my form (edit mode), right click in the column I want to change 4. Click column

Thanks

I’m sorry I don’t see this. I’m new here.

A bug has been reported.
See - here