fields added with action 'in_widget_form' disappear after update in customizer

[Chouby]

I just started testing the new widget preview in customizer. I add a field to all widgets forms using the action 'in_widget_form'. In customizer, the field is correctly displayed at first but disappears after the widget has been updated.

[westonruter]

@Chouby Can you share the full code you're using, including the in_widget_form action usage? If private, please send to weston at x-team.com

[westonruter]

For comparison, the Jetpack Widget Visibility module uses the in_widget_form to inject new fields, but they are not lost upon updating the widget.

[Chouby]

There is nothing private. the plugin is ​Polylang.
In a class PLL_Admin_Filters, I have the method:

public function in_widget_form($widget) {
	$dropdown = new PLL_Walker_Dropdown();
	printf('<p><label for="%1$s">%2$s %3$s</label></p>',
		esc_attr( $widget->id.'_lang_choice'),
		__('The widget is displayed for:', 'polylang'),
		$dropdown->walk(
			array_merge(
				array((object) array('slug' => 0, 'name' => __('All languages', 'polylang'))),
				$this->model->get_languages_list()
			),
			array(
				'name'        => $widget->id.'_lang_choice',
				'class'       => 'tags-input',
				'selected'    => empty($this->options['widgets'][$widget->id]) ? '' : $this->options['widgets'][$widget->id]
			)
		)
	);
}

The method is hooked to the action in the class constructor

add_action('in_widget_form', array(&$this, 'in_widget_form'));

However, looking back at my code I see that the object itself is created in a method hooked to 'wp_loaded'. Could it be too late?

I will look at jetpack to compare.

[Chouby]

I confirm that it works with Jetpack. Making further tests show that replacing 'wp_loaded' by 'init' as done in Jetpack does not change anything for Polylang. I now believe that this is a Polylang bug which does not load correctly on ajax request made by the customizer. Sorry for bothering you with this. I propose to close the ticket as invalid.