diff --git a/layout/xul/base/src/nsXULTooltipListener.cpp b/layout/xul/base/src/nsXULTooltipListener.cpp
index d3a7f96e8012..95cebcca0e42 100644
--- a/layout/xul/base/src/nsXULTooltipListener.cpp
+++ b/layout/xul/base/src/nsXULTooltipListener.cpp
@@ -303,8 +303,8 @@ nsXULTooltipListener::AddTooltipSupport(nsIContent* aNode)
     return NS_ERROR_NULL_POINTER;
 
   nsCOMPtr<nsIDOMEventTarget> evtTarget(do_QueryInterface(aNode));
-  evtTarget->AddEventListener(NS_LITERAL_STRING("mouseout"), (nsIDOMMouseListener*)this, PR_FALSE);
-  evtTarget->AddEventListener(NS_LITERAL_STRING("mousemove"), (nsIDOMMouseListener*)this, PR_FALSE);
+  evtTarget->AddEventListener(NS_LITERAL_STRING("mouseout"), (nsIDOMMouseListener*)this, PR_TRUE);
+  evtTarget->AddEventListener(NS_LITERAL_STRING("mousemove"), (nsIDOMMouseListener*)this, PR_TRUE);
   
   return NS_OK;
 }
@@ -316,8 +316,8 @@ nsXULTooltipListener::RemoveTooltipSupport(nsIContent* aNode)
     return NS_ERROR_NULL_POINTER;
 
   nsCOMPtr<nsIDOMEventTarget> evtTarget(do_QueryInterface(aNode));
-  evtTarget->RemoveEventListener(NS_LITERAL_STRING("mouseout"), (nsIDOMMouseListener*)this, PR_FALSE);
-  evtTarget->RemoveEventListener(NS_LITERAL_STRING("mousemove"), (nsIDOMMouseListener*)this, PR_FALSE);
+  evtTarget->RemoveEventListener(NS_LITERAL_STRING("mouseout"), (nsIDOMMouseListener*)this, PR_TRUE);
+  evtTarget->RemoveEventListener(NS_LITERAL_STRING("mousemove"), (nsIDOMMouseListener*)this, PR_TRUE);
 
   return NS_OK;
 }