diff --git a/content/events/src/nsEventListenerManager.cpp b/content/events/src/nsEventListenerManager.cpp
index f0c3a692259..b649ecfa48c 100644
--- a/content/events/src/nsEventListenerManager.cpp
+++ b/content/events/src/nsEventListenerManager.cpp
@@ -992,7 +992,7 @@ nsEventListenerManager::HandleEventInternal(nsPresContext* aPresContext,
           if (NS_FAILED(HandleEventSubType(ls, ls->mListener, *aDOMEvent,
                                            aCurrentTarget, aFlags,
                                            aPusher))) {
-            aEvent->flags |= NS_EVENT_FLAG_EXCEPTION_THROWN;
+            aEvent->mFlags.mExceptionHasBeenRisen = true;
           }
         }
       }
diff --git a/dom/indexedDB/AsyncConnectionHelper.cpp b/dom/indexedDB/AsyncConnectionHelper.cpp
index c0183198c26..157d99e92b5 100644
--- a/dom/indexedDB/AsyncConnectionHelper.cpp
+++ b/dom/indexedDB/AsyncConnectionHelper.cpp
@@ -449,7 +449,7 @@ AsyncConnectionHelper::OnSuccess()
                mTransaction->IsAborted(),
                "How else can this be closed?!");
 
-  if ((internalEvent->flags & NS_EVENT_FLAG_EXCEPTION_THROWN) &&
+  if (internalEvent->mFlags.mExceptionHasBeenRisen &&
       mTransaction &&
       mTransaction->IsOpen()) {
     rv = mTransaction->Abort(NS_ERROR_DOM_INDEXEDDB_ABORT_ERR);
@@ -485,7 +485,7 @@ AsyncConnectionHelper::OnError()
     nsEvent* internalEvent = event->GetInternalNSEvent();
     NS_ASSERTION(internalEvent, "This should never be null!");
 
-    if ((internalEvent->flags & NS_EVENT_FLAG_EXCEPTION_THROWN) &&
+    if (internalEvent->mFlags.mExceptionHasBeenRisen &&
         mTransaction &&
         mTransaction->IsOpen() &&
         NS_FAILED(mTransaction->Abort(NS_ERROR_DOM_INDEXEDDB_ABORT_ERR))) {
diff --git a/widget/nsGUIEvent.h b/widget/nsGUIEvent.h
index 672a98d6261..88e37cec273 100644
--- a/widget/nsGUIEvent.h
+++ b/widget/nsGUIEvent.h
@@ -120,8 +120,6 @@ enum nsEventStructType {
 
 #define NS_PRIV_EVENT_UNTRUSTED_PERMITTED 0x8000
 
-#define NS_EVENT_FLAG_EXCEPTION_THROWN    0x10000
-
 #define NS_EVENT_RETARGET_TO_NON_NATIVE_ANONYMOUS 0x40000
 
 #define NS_EVENT_FLAG_DONT_FORWARD_CROSS_PROCESS 0x100000
@@ -539,6 +537,9 @@ public:
   // If mIsSynthesizedForTests is true, the event has been synthesized for
   // automated tests or something hacky approach of an add-on.
   bool    mIsSynthesizedForTests : 1;
+  // If mExceptionHasBeenRisen is true, one of the event handlers has risen an
+  // exception.
+  bool    mExceptionHasBeenRisen : 1;
 
   // If the event is being handled in target phase, returns true.
   bool InTargetPhase() const