diff --git a/dom/events/IMEStateManager.cpp b/dom/events/IMEStateManager.cpp
index 71d7b7a62b1..34a06d06fb6 100644
--- a/dom/events/IMEStateManager.cpp
+++ b/dom/events/IMEStateManager.cpp
@@ -146,6 +146,8 @@ GetEventMessageName(uint32_t aMessage)
       return "NS_COMPOSITION_CHANGE";
     case NS_COMPOSITION_COMMIT_AS_IS:
       return "NS_COMPOSITION_COMMIT_AS_IS";
+    case NS_COMPOSITION_COMMIT:
+      return "NS_COMPOSITION_COMMIT";
     default:
       return "unacceptable event message";
   }
diff --git a/editor/libeditor/nsHTMLEditor.cpp b/editor/libeditor/nsHTMLEditor.cpp
index 06a842b6dc0..ff77dcc5d7a 100644
--- a/editor/libeditor/nsHTMLEditor.cpp
+++ b/editor/libeditor/nsHTMLEditor.cpp
@@ -5211,6 +5211,13 @@ nsHTMLEditor::IsAcceptableInputEvent(nsIDOMEvent* aEvent)
     return false;
   }
 
+  // While there is composition, all composition events in its top level window
+  // are always fired on the composing editor.  Therefore, if this editor has
+  // composition, the composition events should be handled in this editor.
+  if (mComposition && aEvent->GetInternalNSEvent()->AsCompositionEvent()) {
+    return true;
+  }
+
   NS_ENSURE_TRUE(mDocWeak, false);
 
   nsCOMPtr<nsIDOMEventTarget> target;