I resolved editing the plugin, to start showing panels, edit:
all-in-one-event-calendar\public\admin\add_new_event_meta_box.php Row 10:
<?php echo 'ai1ec-overflow-visible';//ORIGINAL:echo 0 === $i ? 'ai1ec-overflow-visible' : '' ?>">
\all-in-one-event-calendar\public\admin\box_event_children.php
\all-in-one-event-calendar\public\admin\box_event_contact.php
\all-in-one-event-calendar\public\admin\box_event_cost.php
\all-in-one-event-calendar\public\admin\box_event_location.php
\all-in-one-event-calendar\public\admin\box_time_and_date.php
into the block with panel class approximately
row 10:
<div id="ai1ec-event-*****" class="ai1ec-panel-collapse ai1ec-collapse" >
added the class “ai1ec-in”:
<div id="ai1ec-event-*****" class="ai1ec-panel-collapse ai1ec-collapse ai1ec-in">