Remove redundant spaces from generated contact names

config/defaults.inc.php

@@ -1032,11 +1032,11 @@ $config['addressbook_pagesize'] = 50;
 // sort contacts by this col (preferably either one of name, firstname, surname)
 $config['addressbook_sort_col'] = 'surname';
 
-// the way how contact names are displayed in the list
-// 0: display name
-// 1: (prefix) firstname middlename surname (suffix)
-// 2: (prefix) surname firstname middlename (suffix)
-// 3: (prefix) surname, firstname middlename (suffix)
+// The way how contact names are displayed in the list.
+// 0: prefix firstname middlename surname suffix (only if display name is not set)
+// 1: firstname middlename surname
+// 2: surname firstname middlename
+// 3: surname, firstname middlename
 $config['addressbook_name_listing'] = 0;
 
 // use this timezone to display date/time

program/lib/Roundcube/rcube_addressbook.php

@@ -497,8 +497,11 @@ abstract class rcube_addressbook
         $contact = rcube::get_instance()->plugins->exec_hook('contact_displayname', $contact);
         $fn = $contact['name'];
 
-        if (!$fn)  // default display name composition according to vcard standard
-            $fn = trim(join(' ', array_filter(array($contact['prefix'], $contact['firstname'], $contact['middlename'], $contact['surname'], $contact['suffix']))));
+        // default display name composition according to vcard standard
+        if (!$fn) {
+            $fn = join(' ', array_filter(array($contact['prefix'], $contact['firstname'], $contact['middlename'], $contact['surname'], $contact['suffix'])));
+            $fn = trim(preg_replace('/\s+/', ' ', $fn));
+        }
 
         // use email address part for name
         $email = self::get_col_values('email', $contact, true);
@@ -547,6 +550,7 @@ abstract class rcube_addressbook
         }
 
         $fn = trim($fn, ', ');
+        $fn = preg_replace('/\s+/', ' ', $fn);
 
         // fallbacks...
         if ($fn === '') {