I have the weird problem that an Ajax enabled form that just worked stopped working - and I have not a clue what is causing this and when it stopped to work. The form itself has no changes for months now and I did not find any code updates which may interfere with this form.
The form is defined in its own form class which extends FormBase. The Ajax functionality is added with the following code in buildForm() method:
$form['form_container']['actions']['submit'] = [ '#type' => 'submit', '#value' => 'Submit', '#ajax' => [ 'callback' => '::ajaxResponse' ], '#attributes' => [ 'class' => ['js-show-throbber'] ], '#weight' => -45, ];
In the form class the method is defined:
public function ajaxResponse(array $form, FormStateInterface $form_state)
When I set a breakpoint within this method for XDebug the script never stops, the process within this methods are not running.