diff --git a/plugins/kolab_tags/kolab_tags.js b/plugins/kolab_tags/kolab_tags.js
index e46bbc5b..f844b4bc 100644
--- a/plugins/kolab_tags/kolab_tags.js
+++ b/plugins/kolab_tags/kolab_tags.js
@@ -684,7 +684,8 @@ function tag_remove(props, obj, event)
 
     var postdata = rcmail.selection_post_data(),
         tags = props != '*' ? [props] : $.map(rcmail.env.tags, function(tag) { return tag.uid; }),
-        rc = window.parent && parent.rcmail && parent.remove_tags ? parent.rcmail : rcmail;
+        win = window.parent && parent.rcmail && parent.remove_tags ? parent : window,
+        rc = win.rcmail;
 
     postdata._tag = props;
     postdata._act = 'remove';
@@ -693,7 +694,7 @@ function tag_remove(props, obj, event)
 
     // remove tags from message(s) without waiting to a response
     // in case of an error the list will be refreshed
-    $.each(tags, function() { tag_remove_callback(this); });
+    $.each(tags, function() { win.tag_remove_callback(this); });
 }
 
 // update messages list and message frame after removing tag assignments