diff --git a/web/includes/Filter.php b/web/includes/Filter.php
index f2a8f5b9f..97088498b 100644
--- a/web/includes/Filter.php
+++ b/web/includes/Filter.php
@@ -90,9 +90,12 @@ class Filter extends ZM_Object {
         $this->_querystring .= $term->querystring($objectname, $separator);
       } # end foreach term
       $this->_querystring .= $separator.urlencode($objectname.'[Query][sort_asc]').'='.$this->sort_asc();
-      $this->_querystring .= $separator.urlencode($objectname.'[Query][sort_field]').'='.$this->sort_field();
-      $this->_querystring .= $separator.urlencode($objectname.'[Query][skip_locked]').'='.$this->skip_locked();
-      $this->_querystring .= $separator.urlencode($objectname.'[Query][limit]').'='.$this->limit();
+      if ($this->sort_field())
+        $this->_querystring .= $separator.urlencode($objectname.'[Query][sort_field]').'='.$this->sort_field();
+      if ($this->skip_locked())
+        $this->_querystring .= $separator.urlencode($objectname.'[Query][skip_locked]').'='.$this->skip_locked();
+      if ($this->limit())
+        $this->_querystring .= $separator.urlencode($objectname.'[Query][limit]').'='.$this->limit();
       if ( $this->Id() ) {
         $this->_querystring .= $separator.$objectname.urlencode('[Id]').'='.$this->Id();
       }