diff --git a/program/js/app.js b/program/js/app.js
index f6822a9d0..d3c1cc221 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -5243,7 +5243,8 @@ function rcube_webmail()
     this.set_caret_pos(this.ksearch_input, p + insert.length);
 
     if (trigger) {
-      this.triggerEvent('autocomplete_insert', { field:this.ksearch_input, insert:insert, data:this.env.contacts[id] });
+      this.triggerEvent('autocomplete_insert', { field:this.ksearch_input, insert:insert, data:this.env.contacts[id], search:this.ksearch_value_last, result_type:'person' });
+      this.ksearch_value_last = null;
       this.compose_type_activity++;
     }
   };
@@ -5252,7 +5253,8 @@ function rcube_webmail()
   {
     if (this.group2expand[id]) {
       this.group2expand[id].input.value = this.group2expand[id].input.value.replace(this.group2expand[id].name, recipients);
-      this.triggerEvent('autocomplete_insert', { field:this.group2expand[id].input, insert:recipients });
+      this.triggerEvent('autocomplete_insert', { field:this.group2expand[id].input, insert:recipients, data:this.group2expand[id], search:this.ksearch_value_last, result_type:'group' });
+      this.ksearch_value_last = null;
       this.group2expand[id] = null;
       this.compose_type_activity++;
     }
@@ -5295,6 +5297,7 @@ function rcube_webmail()
 
     var old_value = this.ksearch_value;
     this.ksearch_value = q;
+    this.ksearch_value_last = q;   // Group expansion clears ksearch_value before calling autocomplete_insert trigger, therefore store it in separate variable for later consumption.
 
     // ...string is empty
     if (!q.length)
diff --git a/program/steps/mail/autocomplete.inc b/program/steps/mail/autocomplete.inc
index 3023ecfb7..31480ca76 100644
--- a/program/steps/mail/autocomplete.inc
+++ b/program/steps/mail/autocomplete.inc
@@ -58,14 +58,14 @@ else {
     $book_types = (array) $RCMAIL->config->get('autocomplete_addressbooks', 'sql');
 }
 
+$contacts = array();
 if (!empty($book_types) && strlen($search)) {
-    $contacts  = array();
     $sort_keys = array();
     $books_num = count($book_types);
     $search_lc = mb_strtolower($search);
 
-    foreach ($book_types as $id) {
-        $abook = $RCMAIL->get_address_book($id);
+    foreach ($book_types as $abook_id) {
+        $abook = $RCMAIL->get_address_book($abook_id);
         $abook->set_pagesize($MAXNUM);
 
         if ($result = $abook->search($RCMAIL->config->get('contactlist_fields'), $search, $mode, true, true, 'email')) {
@@ -92,7 +92,12 @@ if (!empty($book_types) && strlen($search)) {
 
                     // skip duplicates
                     if (empty($contacts[$index])) {
-                        $contact = array('name' => $contact, 'type' => $sql_arr['_type']);
+                        $contact = array(
+                            'name'   => $contact,
+                            'type'   => $sql_arr['_type'],
+                            'id'     => $sql_arr['contact_id'],
+                            'source' => $abook_id,
+                        );
 
                         if (($display = rcube_addressbook::compose_search_name($sql_arr, $email, $name)) && $display != $contact['name']) {
                             $contact['display'] = $display;
@@ -135,7 +140,7 @@ if (!empty($book_types) && strlen($search)) {
                                 'email'  => $email,
                                 'type'   => 'group',
                                 'id'     => $group['ID'],
-                                'source' => $id,
+                                'source' => $abook_id,
                             );
 
                             if (count($contacts) >= $MAXNUM) {
@@ -152,7 +157,7 @@ if (!empty($book_types) && strlen($search)) {
                             'name'   => $group['name'] . ' (' . intval($result->count) . ')',
                             'type'   => 'group',
                             'id'     => $group['ID'],
-                            'source' => $id
+                            'source' => $abook_id,
                         );
 
                         if (count($contacts) >= $MAXNUM) {
@@ -175,5 +180,14 @@ if (!empty($book_types) && strlen($search)) {
     }
 }
 
+
+// Allow autocomplete result optimization via plugin
+$pluginResult = $RCMAIL->plugins->exec_hook('contacts_autocomplete_after', array(
+    'search'   => $search,
+    'contacts' => $contacts, // Provide already-found contacts to plugin if they are required
+));
+$contacts = $pluginResult['contacts'];
+
+
 $OUTPUT->command('ksearch_query_results', $contacts, $search, $reqid);
 $OUTPUT->send();