diff --git a/mozilla/toolkit/content/widgets/tabbrowser.xml b/mozilla/toolkit/content/widgets/tabbrowser.xml
index 138ab46871f..f4290b072c7 100644
--- a/mozilla/toolkit/content/widgets/tabbrowser.xml
+++ b/mozilla/toolkit/content/widgets/tabbrowser.xml
@@ -572,7 +572,7 @@
                 if (listener.mIcon) {
                   if (this.isFavIconKnownMissing(listener.mIcon))
                     listener.mIcon = null;
-                  else
+                  else if ('onLinkIconAvailable' in p)
                     p.onLinkIconAvailable(newBrowser, listener.mIcon);
                 }
               }
@@ -743,7 +743,7 @@
               var targetBrowser = tabBrowser.getBrowserAtIndex(browserIndex);
               for (i = 0; i < tabBrowser.mProgressListeners.length; i++) {
                 var p = tabBrowser.mProgressListeners[i];
-                if (p)
+                if (p && 'onLinkIconAvailable' in p)
                   p.onLinkIconAvailable(targetBrowser, href);
               }
             }
diff --git a/mozilla/xpfe/global/resources/content/bindings/tabbrowser.xml b/mozilla/xpfe/global/resources/content/bindings/tabbrowser.xml
index 56e9762843f..3fdff4e2dc5 100644
--- a/mozilla/xpfe/global/resources/content/bindings/tabbrowser.xml
+++ b/mozilla/xpfe/global/resources/content/bindings/tabbrowser.xml
@@ -527,7 +527,7 @@
                 if (securityUI)
                   p.onSecurityChange(webProgress, null, securityUI.state);
                 var listener = this.mTabListeners[this.mPanelContainer.selectedIndex];
-                if (listener.mIcon)
+                if (listener.mIcon && 'onLinkIconAvailable' in p)
                   p.onLinkIconAvailable(listener.mIcon);
               }
             }
@@ -696,7 +696,7 @@
             if (notifyListeners && this.mProgressListeners) {
               for (i = 0; i < this.mProgressListeners.length; i++) {
                 var p = this.mProgressListeners[i];
-                if (p)
+                if (p && 'onLinkIconAvailable' in p)
                   p.onLinkIconAvailable(href);
               }
             }