Summary:Project:Support desk/No Notification tab in preferences

It was because in my LocalSetting there are these  2 lines :
$wgGroupPermissions['*']['viewmywatchlist'] = false;
$wgGroupPermissions['*']['editmywatchlist'] = false;

after replacement by 
$wgGroupPermissions['user']['viewmywatchlist'] = true;
$wgGroupPermissions['user']['editmywatchlist'] = true;

the orange bar ''you have a message'' is correctly removed after reading
and the preferences "notification tab" is displayed only when the ''extension:echo'' is installed