Warning: foreach() argument must be of type array|object, null given

Problem/Motivation

Hi there,

Drupal 9.5.11
Footable dev-2.x (but others too)

Views settings don't load after I choose the "Footable" format; in the log:

http://****/admin/structure/views/ajax/display/progetti/page_1/style_options?_wrapper_format=drupal_ajax

Warning: foreach() argument must be of type array|object, null given in Drupal\Core\Render\Element\Checkboxes::valueCallback() (linea 113 di ***/core/lib/Drupal/Core/Render/Element/Checkboxes.php).

Steps to reproduce

Proposed resolution

Basically i changed

220: '#default_value' => $this->options['footable']['breakpoint'][$name] ?? NULL,
to
'#default_value' => $this->options['footable']['breakpoint'][$name] ?? [],
in src/Plugin/views/style/FooTable.php

Seems to work.