diff --git a/content/xul/content/src/nsXULElement.cpp b/content/xul/content/src/nsXULElement.cpp
index a78f353dc82..a2d22764957 100644
--- a/content/xul/content/src/nsXULElement.cpp
+++ b/content/xul/content/src/nsXULElement.cpp
@@ -1448,7 +1448,7 @@ nsXULElement::IsFocusable(PRInt32 *aTabIndex)
     *aTabIndex = tabIndex;
   }
 
-  return !disabled;
+  return tabIndex >= 0;
 }