Unable to remove a report from the navigation menu

While adding a report to the navigation menu (edit the report and check the box) works fine.
Removing a already added report raises the following warning and doesn't work (still in the menu) :

"""
Notice : Undefined index: label dans CRM_Core_BAO_Navigation::add() (ligne 110 dans /var/www/drupal/sites/all/modules/civicrm/CRM/Core/BAO/Navigation.php).
Notice : Undefined index: permission dans CRM_Core_BAO_Navigation::add() (ligne 116 dans /var/www/drupal/sites/all/modules/civicrm/CRM/Core/BAO/Navigation.php).
"""
1- There is no way to remove an item from the navigation bar, it's only possible to disable it.
2- The 'add(' method used for both adding and updating an element is called with a void parameter which causes the raised warning

The attached patch, affects the CRM/Report/Form/Instance.php file.
What it does, on disabling:

• provide the needed value to avoid the warning
• set the navigation_id param to NULL in the CRM_Report_DAO_Instance