How to Restore the old WP Widgets Editor

The recent WordPress update changed the way to edit the widgets on this page:
wp-admin/widgets.php

Instead of having the classic widgets dashboard

new wp widgets

you now work with a problematic block editor to manage the widgets

To restore the old functionality that made sense just find the file functions.php in your theme folder (if you have a child theme use the child theme’s functions.php instead).

restore old wp widgets

go to the end of the file and add this code in a new line
add_filter( 'use_widgets_block_editor', '__return_false' );

To disable the old functionality, find again the line and add a comment like this:
//add_filter( 'use_widgets_block_editor', '__return_false' );