diff --git a/src/js/tab.js b/src/js/tab.js
index e2f0c0a01..f4929bf30 100644
--- a/src/js/tab.js
+++ b/src/js/tab.js
@@ -177,7 +177,7 @@ housekeep itself.
             //   If the trigger is a change in the opener's URL, mark the entry
             //   as candidate for popunder filtering.
             if ( targetTabId === entry.opener.tabId ) {
-                entry.popunder = true;
+                entry.opener.popunder = true;
             }
             if ( vAPI.tabs.onPopupUpdated(tabId, entry.opener) === true ) {
                 entry.destroy();