--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -433,16 +433,23 @@ var gPopupBlockerObserver = {
 
     if (!this._reportButton && gURLBar)
       this._reportButton = document.getElementById("page-report-button");
 
     if (!gBrowser.selectedBrowser.blockedPopups) {
       // Hide the icon in the location bar (if the location bar exists)
       if (gURLBar)
         this._reportButton.hidden = true;
+
+      // Hide the notification box (if it's visible).
+      var notificationBox = gBrowser.getNotificationBox();
+      var notification = notificationBox.getNotificationWithValue("popup-blocked");
+      if (notification) {
+        notificationBox.removeNotification(notification, false);
+      }
       return;
     }
 
     if (gURLBar)
       this._reportButton.hidden = false;
 
     // Only show the notification again if we've not already shown it. Since
     // notifications are per-browser, we don't need to worry about re-adding