The pager on a form doesn't update upon first submit of the form

Question

I have a form with filter checkboxes, submit button, results in tableselect and pager.

When I set some checkboxes and press the submit button, a query should be reexecuted, data should be placed into the tableselect and pager should be updated, because new data size can be different with old one.

When I do it the first time, query is executed successfully, tableselect also is updated without problems. But the pager doesn't want to be updated. And to update the pager I have to press the submit button second time. But it occurs only I pressed the submit button after the page with the form has been loaded.

Could you clarify me, how can I update the pager after first submission of the form ?

Here is a fragment of my code with the tableselect and the pager.

$q = \Drupal::entityQuery('node');
        $q = $q->condition('type', 'my_node_type')
            ->condition('status', 1);

        $pager_params = [];
        if ($event_types != []){
            $q->condition('field_art_der_veranstaltung', $event_types, 'IN');
        }

        $events = $q->sort('created', 'DESC')->pager(10)->execute();

        $nodes = Node::loadMultiple($events);

        $rows = [];

        foreach($nodes as $node){
            $rows[$node->id()] = [
                'nid' => $node->id(),
                'title' => $node->getTitle(),
            ];
        };

        $form['nodes_container']['nodes'] = [
            '#type' => 'tableselect',
            '#title' => $this->t('Events'),
            '#options' => $rows,
            '#header' => $header,
            '#empty' => $this->t('No events found'),
        ];

        $form['nodes_container']['pager'] = [
            '#type' => 'pager',
        ];

Answer 1

Seemingly, I have fould the solution. Namely, to avoid it, I set the Element property for the pager explicitely.

Here are fragments of code.

$nodes = $q->sort('created', 'DESC')->pager(10, 0)->execute();

/// code here

$form['nodes_container']['pager'] = [
  '#type' => 'pager',
  '#element' => 0,
  '#parameters' => $pager_params,
];

Unfortunately, I didn't have a time to debug and find out why it didn't worked before but it works now. Newertheless, it works.