Panel description in Customizer does not show up

Like above, when I add Panel to Customizer, its description does not show up. Moreover, section description shows correctly. Even more, the element in DOM exists but it has display:none; property inherited from some default styles. This is what I’m doing:

$wp_customize->add_panel('mypanel', array(
    'title'         => __('My awesome panel', 'domain'),
    'description'   => __("This is the description which doesn't want to show up :(", 'domain'),
    'capability'    => 'edit_theme_options',
    'priority'      => 2
));

$wp_customize->add_section('mysection', array(
    'title'    => __('My even more awesome section', 'domain'),
    'panel'    => 'mypanel',
    'description' => __('Section description which does show up', 'domain')
));

$wp_customize->add_setting('mysetting', array(
    'settings'          => 'mysection',
    'capability'        => 'edit_theme_options',
    'sanitize_callback' => 'sanitize_text_field'
    ));

$wp_customize->add_control('mycontrol', array(
    'label'   => __('The most awesome control', 'domain'),
    'section' => 'mysection',
    'type'    => 'text'
));

Like I said, the description <div> actually exists in DOM structure but it has CSS style which blocks its displaying:

HTML:
enter image description here

CSS:
enter image description here

QUESTION: Why is it happening and how can I make the description visible?

Solutions Collecting From Web of "Panel description in Customizer does not show up"

I needed to tweak the settings and controls code a bit to get them to work:

$wp_customize->add_panel('mypanel', array(
        'title'         => __('My awesome panel', 'domain'),
        'description'   => __("This is the description which doesn't want to show up :(", 'domain'),
        'capability'    => 'edit_theme_options',
        'priority'      => 2
));

$wp_customize->add_section('mysection', array(
        'title'    => __('My even more awesome section', 'domain'),
        'panel'    => 'mypanel',
        'description' => __('Section description which does show up', 'domain')
));

$wp_customize->add_setting('mysetting', array(
        'capability'        => 'edit_theme_options',
        'sanitize_callback' => 'sanitize_text_field'
        ));

$wp_customize->add_control('mycontrol', array(
        'settings' => 'mysetting',
        'label'   => __('The most awesome control', 'domain'),
        'section' => 'mysection',
        'type'    => 'text'
));

The main thing here is that Panel descriptions are only shown once the ? icon is clicked:

Reveal Panel description