diff --git a/include/ajax/ajax_search_filter.php b/include/ajax/ajax_search_filter.php
index c27458f11..dbf010956 100644
--- a/include/ajax/ajax_search_filter.php
+++ b/include/ajax/ajax_search_filter.php
@@ -213,6 +213,7 @@ if ($op=="delete_search_operation")
 if ($op=='display_filter_tag')
 {
     $tag=$http->request("uf_tag");
+    if ( trim($tag)=="") {return;}
     $div=$http->request("div");
     $aTag=explode(',', $tag);
     if (is_array($aTag))
diff --git a/include/class/tag.class.php b/include/class/tag.class.php
index 5672adf08..5b2097e34 100644
--- a/include/class/tag.class.php
+++ b/include/class/tag.class.php
@@ -25,6 +25,7 @@ class Tag
     function __construct($p_cn,$id=-1)
     {
         $this->cn=$p_cn;
+        $id = (trim($id)=="")?-1:$id;
         $this->data=new Tag_SQL($p_cn,$id);
     }
     public function get_data()