diff --git a/toolkit/content/widgets/tabbrowser.xml b/toolkit/content/widgets/tabbrowser.xml
index ae06c009f9b..1a018906e66 100644
--- a/toolkit/content/widgets/tabbrowser.xml
+++ b/toolkit/content/widgets/tabbrowser.xml
@@ -85,6 +85,7 @@
                     ondragdrop="nsDragAndDrop.drop(event, this.parentNode.parentNode.parentNode);
                                 event.stopPropagation();"
                     xbl:inherits="onnewtab"
+                    ondblclick="if (event.target.localName == 'tabs') this.parentNode.parentNode.parentNode.addTab();"
                     onclosetab="var node = this.parentNode;
                                 while (node.localName != 'tabbrowser')
                                   node = node.parentNode;