Yes I check the code also and you're right. I had something not 
working and was wondering if there was no mistake as in some prefs, 
you're using \t and in another \n

May be, it would be better to accept \n or \t..



in turba/config/prefs.php



// Address books to be displayed in the address book selection widget

// and in the Browse menu item.  The address book name is stored using

// the source key from sources.php (e.g. "localsql").  Separate

// entries with "\n" , e. g. 'value' => "localsql\nlocalldap" (the

// double quotes are REQUIRED).  If 'value' is empty (''), all address

// books that the user has permissions to will be listed.



in kronolith/config/prefs.php



// address book(s) to use when expanding addresses

// You can provide default values this way (note the \t and the double 
quotes):

// 'value' => "source_one\tsource_two"

// refer to turba/config/sources.php for possible source values

$_prefs['search_sources'] = array(

     'value' => "localldap\tlocalsql",

     'locked' => true,

     'shared' => false,

     'type' => 'implicit',

);

$lines = explode("\n", $GLOBALS['prefs']->getValue('addressbooks'));



etc. \n is correct.

BAD comment, it's not \n but \t. It's not working with \n



// Address books to be displayed in the address book selection widget

// and in the Browse menu item.  The address book name is stored using

// the source key from sources.php (e.g. "localsql").  Separate

// entries with "\n" , e. g. 'value' => "localsql\nlocalldap" (the

// double quotes are REQUIRED).  If 'value' is empty (''), all address

// books that the user has permissions to will be listed.

$_prefs['addressbooks'] = array(

     'value' => "localsql\tlocalldap",

     'locked' => true,

     'shared' => false,

     'type' => 'implicit',

);