diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 0ff4db19bb7..2e711da4079 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -713,7 +713,7 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
     break;
   case eWheel:
   case eWheelOperationStart:
-  case NS_WHEEL_STOP:
+  case eWheelOperationEnd:
     {
       NS_ASSERTION(aEvent->mFlags.mIsTrusted,
                    "Untrusted wheel event shouldn't be here");
@@ -3008,7 +3008,7 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
       }
     }
     break;
-  case NS_WHEEL_STOP:
+  case eWheelOperationEnd:
     {
       MOZ_ASSERT(aEvent->mFlags.mIsTrusted);
       ScrollbarsForWheel::MayInactivate();
diff --git a/dom/events/WheelHandlingHelper.h b/dom/events/WheelHandlingHelper.h
index 11c0cabbbc8..4b37eb04342 100644
--- a/dom/events/WheelHandlingHelper.h
+++ b/dom/events/WheelHandlingHelper.h
@@ -95,8 +95,8 @@ protected:
 
 
   /**
-   * These two methods are called upon eWheelOperationStart/NS_WHEEL_STOP events
-   * to show/hide the right scrollbars.
+   * These two methods are called upon eWheelOperationStart/eWheelOperationEnd
+   * events to show/hide the right scrollbars.
    */
   static void TemporarilyActivateAllPossibleScrollTargets(
                 EventStateManager* aESM,
diff --git a/layout/base/AccessibleCaretEventHub.cpp b/layout/base/AccessibleCaretEventHub.cpp
index 867f46e3367..42ccd112448 100644
--- a/layout/base/AccessibleCaretEventHub.cpp
+++ b/layout/base/AccessibleCaretEventHub.cpp
@@ -545,8 +545,8 @@ AccessibleCaretEventHub::HandleWheelEvent(WidgetWheelEvent* aEvent)
     mState->OnScrollStart(this);
     break;
 
-  case NS_WHEEL_STOP:
-    AC_LOGV("NS_WHEEL_STOP, state: %s", mState->Name());
+  case eWheelOperationEnd:
+    AC_LOGV("eWheelOperationEnd, state: %s", mState->Name());
     mState->OnScrollEnd(this);
     break;
 
diff --git a/layout/base/TouchCaret.cpp b/layout/base/TouchCaret.cpp
index a8e16e23d0d..f473869753f 100644
--- a/layout/base/TouchCaret.cpp
+++ b/layout/base/TouchCaret.cpp
@@ -788,7 +788,7 @@ TouchCaret::HandleEvent(WidgetEvent* aEvent)
     case eKeyPress:
     case eWheel:
     case eWheelOperationStart:
-    case NS_WHEEL_STOP:
+    case eWheelOperationEnd:
       // Disable touch caret while key/wheel event is received.
       TOUCHCARET_LOG("Receive key/wheel event %d", aEvent->mMessage);
       SetVisibility(false);
diff --git a/layout/base/gtest/TestAccessibleCaretEventHub.cpp b/layout/base/gtest/TestAccessibleCaretEventHub.cpp
index 62716cda0fd..7a3663bdcab 100644
--- a/layout/base/gtest/TestAccessibleCaretEventHub.cpp
+++ b/layout/base/gtest/TestAccessibleCaretEventHub.cpp
@@ -742,7 +742,7 @@ TEST_F(AccessibleCaretEventHubTester, TestWheelEventScroll)
 
   mHub->ScrollPositionChanged();
 
-  HandleEventAndCheckState(CreateWheelEvent(NS_WHEEL_STOP),
+  HandleEventAndCheckState(CreateWheelEvent(eWheelOperationEnd),
                            MockAccessibleCaretEventHub::PostScrollState(),
                            nsEventStatus_eIgnore);
 
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index 5a07a23a274..187919d4e8b 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -389,7 +389,10 @@ NS_EVENT_MESSAGE(eWheel,                 eWheelEventFirst)
 // wheel.  This won't be fired on some platforms which don't have corresponding
 // native event.
 NS_EVENT_MESSAGE(eWheelOperationStart,   eWheelEventFirst + 1)
-NS_EVENT_MESSAGE(NS_WHEEL_STOP,          eWheelEventFirst + 2)
+// eWheelOperationEnd may be dispatched when user ends or cancels operating
+// mouse wheel.  This won't be fired on some platforms which don't have
+// corresponding native event.
+NS_EVENT_MESSAGE(eWheelOperationEnd,     eWheelEventFirst + 2)
 
 //System time is changed
 NS_EVENT_MESSAGE(NS_MOZ_TIME_CHANGE_EVENT, 5500)
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 6054939fc0d..7888a8eacf0 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -4896,17 +4896,17 @@ PanGestureTypeForEvent(NSEvent* aEvent)
   }
 
   NSEventPhase phase = nsCocoaUtils::EventPhase(theEvent);
-  // Fire eWheelOperationStart/STOP events when 2 fingers touch/release the
+  // Fire eWheelOperationStart/End events when 2 fingers touch/release the
   // touchpad.
   if (phase & NSEventPhaseMayBegin) {
     [self sendWheelCondition:YES
-                       first:NS_WHEEL_STOP
+                       first:eWheelOperationEnd
                       second:eWheelOperationStart
                     forEvent:theEvent];
   } else if (phase & (NSEventPhaseEnded | NSEventPhaseCancelled)) {
     [self sendWheelCondition:NO
                        first:eWheelOperationStart
-                      second:NS_WHEEL_STOP
+                      second:eWheelOperationEnd
                     forEvent:theEvent];
   }