Hitting the delete button should show you a confirmation popup "Do you want to remove the file reference from this record?..."
Ok.. so the problem is here, I don't have any popup requests .. it doesn't eit in front nor in back
It's definitivly working even with php7.4 (although official Fabrik3.2 is not php7.4 ready, showing those "deprecated" messges; there are several fixes in GitHub)
so you advise me to leave it, or set an older version?
So if you don't get this popup it must be something in your setup.
e.g. 3rd-party stuff injecting own JS or CSS, folder permissions, fileupload element settings ...
the problem is that there is nothing installed, the only component is akeeba, the template is the default "protostar" ... the same error appeared to me locally with MAMP
one thing I noticed, is the problem of opening the calendar, which I installed yesterday. the form does not open to select the fairy, so I think the problem is actually related to some JS or CSS but I just can't solve it.