custom post type not available for all users…

Hello,

I’ve created a little plugin to set a new post type that I named ‘event’. It works fine when I’m connected as super-admin, but not when I try to log in as an other role user (author, admin,…). For these last users all is ok but the event creation window where the metaboxes doesn’t display. Here’s the code :

<?php

/*
Plugin Name: VSAW - Very Simple Agenda for WordPress
Plugin URI: http://perso.jojaba.fr/
Description: Provides a very simple way to define events.
Author: Jojaba
Version: 1.0
Author URI: http://perso.jojaba.fr/
*/

/**
 * Custom posts for agenda called event
 */
 function events_custom_init() {
  $labels = array(
    'name'               => 'Évènements',
    'singular_name'      => 'Évènement',
    'add_new'            => 'Nouveau',
    'add_new_item'       => 'Ajouter un évènement',
    'edit_item'          => 'Modifier l\'évènement',
    'new_item'           => 'Nouvel évènement',
    'all_items'          => 'Tous les évènements',
    'view_item'          => 'Afficher l\'évènement',
    'search_items'       => 'Rechercher des évènements',
    'parent_item_colon'  => '',
    'menu_name'          => 'Évènements'
  );

  $args = array(
    'labels'             => $labels,
    'public'             => true,
    'publicly_queryable' => true,
    'show_ui'            => true,
    'show_in_menu'       => true,
    'menu_position' 	 => 5,
    'query_var'          => true,
    'rewrite'            => array( 'slug' => 'agenda' ),
    'capability_type'    => 'post',
    'has_archive'        => true,
    'hierarchical'       => false,
    'supports'           => array( 'title' )
  );

  register_post_type( 'event', $args );
}
add_action( 'init', 'events_custom_init' );

/**
 * Adds a meta box to the post editing screen
 */
function vsaw_custom_meta() {
	add_meta_box( 'vsaw_meta', __( 'Informations sur l\'évènement', 'vsaw-textdomain' ), 'vsaw_meta_callback', 'event', 'high' );
}
add_action( 'add_meta_boxes', 'vsaw_custom_meta' );

/**
 * Outputs the content of the meta box
 */
function vsaw_meta_callback( $post ) {
	wp_nonce_field( basename( __FILE__ ), 'vsaw_nonce' );
	$vsaw_stored_meta = get_post_meta( $post->ID );
	?>

	<p class="start_date">
		<label for="meta-start-date"><?php _e( 'Début de l\'évènement', 'vsaw-textdomain' )?></label><br>
		<input required type="text" name="meta-start-date" id="meta-start-date" value="<?php if ( isset ( $vsaw_stored_meta['meta-start-date'] ) ) echo $vsaw_stored_meta['meta-start-date'][0]; ?>" />
	</p>

	<p class="end_date">
		<label for="meta-end-date"><?php _e( 'Fin de l\'évènement', 'vsaw-textdomain' )?></label><br>
		<input type="text" name="meta-end-date" id="meta-end-date" value="<?php if ( isset ( $vsaw_stored_meta['meta-end-date'] ) ) echo $vsaw_stored_meta['meta-end-date'][0]; ?>" />
	</p>

	<p class="location">
		<label for="meta-loc"><?php _e( 'Lieu', 'vsaw-textdomain' )?></label><br>
		<input required type="text" name="meta-loc" id="meta-loc" value="<?php if ( isset ( $vsaw_stored_meta['meta-loc'] ) ) echo $vsaw_stored_meta['meta-loc'][0]; ?>" />
	</p>

	<p class="url">
		<label for="meta-url"><?php _e( 'URL (facultatif)', 'vsaw-textdomain' )?></label><br>
		<input type="text" name="meta-url" id="meta-url" value="<?php if ( isset ( $vsaw_stored_meta['meta-url'] ) ) echo $vsaw_stored_meta['meta-url'][0]; ?>" />
	</p>

	<script>
	/* The date picker displaying */
    jQuery(document).ready(function(){
    		jQuery("#meta-start-date, #meta-end-date").on("click", function() {
    				jQuery(this).pickadate();
    		});
    });
    </script> 

	<?php
}

/**
 * Saves the custom meta input
 */
function vsaw_meta_save( $post_id ) {

	// Checks save status
	$is_autosave = wp_is_post_autosave( $post_id );
	$is_revision = wp_is_post_revision( $post_id );
	$is_valid_nonce = ( isset( $_POST[ 'vsaw_nonce' ] ) && wp_verify_nonce( $_POST[ 'vsaw_nonce' ], basename( __FILE__ ) ) ) ? 'true' : 'false';

	// Exits script depending on save status
	if ( $is_autosave || $is_revision || !$is_valid_nonce ) {
		return;
	}

	// Checks for start date input and sanitizes/saves if needed
	if( isset( $_POST[ 'meta-start-date' ] ) ) {
		update_post_meta( $post_id, 'meta-start-date', sanitize_text_field( $_POST[ 'meta-start-date' ] ) );
	}

	if( isset( $_POST[ 'meta-start-date_submit' ] ) ) {
		update_post_meta( $post_id, 'meta-start-date_submit', sanitize_text_field( $_POST[ 'meta-start-date_submit' ] ) );
	}

	// Checks for end date input and sanitizes/saves if needed
	if( isset( $_POST[ 'meta-end-date' ] ) ) {
		update_post_meta( $post_id, 'meta-end-date', sanitize_text_field( $_POST[ 'meta-end-date' ] ) );
	}

	if( isset( $_POST[ 'meta-end-date_submit' ] ) ) {
		update_post_meta( $post_id, 'meta-end-date_submit', sanitize_text_field( $_POST[ 'meta-end-date_submit' ] ) );
	}

	// Checks for location input and sanitizes/saves if needed
	if( isset( $_POST[ 'meta-loc' ] ) ) {
		update_post_meta( $post_id, 'meta-loc', sanitize_text_field( $_POST[ 'meta-loc' ] ) );
	}

	// Checks for url input and sanitizes/saves if needed
	if( isset( $_POST[ 'meta-url' ] ) ) {
		update_post_meta( $post_id, 'meta-url', sanitize_text_field( $_POST[ 'meta-url' ] ) );
	}

}
add_action( 'save_post', 'vsaw_meta_save' );

/**
 * Adds the meta box stylesheet when appropriate
 */
function vsaw_admin_styles(){
	global $typenow;
	if( $typenow == 'event' ) {
		wp_enqueue_style( 'vsaw_meta_box_styles', plugin_dir_url( __FILE__ ) . 'vsaw.css' );
	}
}
add_action( 'admin_print_styles', 'vsaw_admin_styles' );

/**
 * Loads the date picker js and css
 */
function vsaw_date_enqueue() {
	global $typenow;
	if( $typenow == 'event' ) {
		wp_enqueue_style( 'vsaw_picker_style', plugin_dir_url( __FILE__ ) . 'pickadate/lib/themes/default.css' );
		wp_enqueue_style( 'vsaw_date_style', plugin_dir_url( __FILE__ ) . 'pickadate/lib/themes/default.date.css' );
		wp_enqueue_script( 'vsaw-box-picker-js', plugin_dir_url( __FILE__ ) . 'pickadate/lib/picker.js' );
		wp_enqueue_script( 'vsaw-box-date-js', plugin_dir_url( __FILE__ ) . 'pickadate/lib/picker.date.js' );
		wp_enqueue_script( 'vsaw-box-legacy-js', plugin_dir_url( __FILE__ ) . 'pickadate/lib/legacy.js' );
		wp_enqueue_script( 'vsaw-box-fr-js', plugin_dir_url( __FILE__ ) . 'pickadate/lib/translations/fr_FR.js' );
	}
}
add_action( 'admin_enqueue_scripts', 'vsaw_date_enqueue' );

Problem of capabilities ? (I thought, they are inherited from the ‘post’ type…)

Thanks in advance.