Fix js error on operator change

plugins/managesieve/managesieve.js

@@ -603,10 +603,12 @@ function rule_header_select(id)
 
 function rule_op_select(obj, id, header)
 {
-  var target = document.getElementById('rule_target' + id + '_list'),
-    style = obj.value == 'exists' || obj.value == 'notexists' || header == 'size' ? 'none' : 'inline-block';
+  var target = document.getElementById('rule_target' + id + '_list');
 
-  target.style.display = style;
+  if (!header)
+    header = document.getElementById('header' + id).value;
+
+  target.style.display = obj.value == 'exists' || obj.value == 'notexists' || header == 'size' ? 'none' : 'inline-block';
 };
 
 function rule_trans_select(id)

plugins/managesieve/managesieve.php

@@ -1353,7 +1353,7 @@ class managesieve extends rcube_plugin
         $select_op = new html_select(array('name' => "_rule_op[]", 'id' => 'rule_op'.$id,
             'style' => 'display:' .($rule['test']!='size' ? 'inline' : 'none'),
             'class' => 'operator_selector',
-            'onchange' => 'rule_op_select('.$id.')'));
+            'onchange' => 'rule_op_select(this, '.$id.')'));
         $select_op->add(rcube::Q($this->gettext('filtercontains')), 'contains');
         $select_op->add(rcube::Q($this->gettext('filternotcontains')), 'notcontains');
         $select_op->add(rcube::Q($this->gettext('filteris')), 'is');