@meneldil
I had the same request on a recent client site, and I’m enqueuing a script into the admin area to generate a confirmation message when trying to delete a layout.
;(function($) {
acf.add_action('ready', function(){
$('body').on('click', '.acf-flexible-content [data-event=remove-layout]', function( e ){
return confirm("Delete row?");
});
});
}(jQuery));