diff --git a/widget/windows/KeyboardLayout.cpp b/widget/windows/KeyboardLayout.cpp
index 3d912c96eede..bdb8b532980b 100644
--- a/widget/windows/KeyboardLayout.cpp
+++ b/widget/windows/KeyboardLayout.cpp
@@ -1847,14 +1847,14 @@ NativeKey::HandleKeyDownMessage(bool* aEventDispatched) const
   }
 
   if (defaultPrevented) {
-    DispatchPluginEventsAndDiscardsCharMessages();
+    MaybeDispatchPluginEventsForRemovedCharMessages();
     return true;
   }
 
   // If we won't be getting a WM_CHAR, WM_SYSCHAR or WM_DEADCHAR, synthesize a
   // keypress for almost all keys
   if (NeedsToHandleWithoutFollowingCharMessages()) {
-    return (DispatchPluginEventsAndDiscardsCharMessages() ||
+    return (MaybeDispatchPluginEventsForRemovedCharMessages() ||
             DispatchKeyPressEventsWithoutCharMessage());
   }
 
@@ -2386,14 +2386,15 @@ NativeKey::GetFollowingCharMessage(MSG& aCharMsg) const
   return false;
 }
 
-// TODO: Rename this method later.
 bool
-NativeKey::DispatchPluginEventsAndDiscardsCharMessages() const
+NativeKey::MaybeDispatchPluginEventsForRemovedCharMessages() const
 {
   MOZ_ASSERT(IsKeyDownMessage());
   MOZ_ASSERT(!IsKeyMessageOnPlugin());
 
-  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+  for (size_t i = 0;
+       i < mFollowingCharMsgs.Length() && mWidget->ShouldDispatchPluginEvent();
+       ++i) {
     MOZ_RELEASE_ASSERT(!mWidget->Destroyed(),
       "NativeKey tries to dispatch a plugin event on destroyed widget");
     mWidget->DispatchPluginEvent(mFollowingCharMsgs[i]);
@@ -2404,7 +2405,9 @@ NativeKey::DispatchPluginEventsAndDiscardsCharMessages() const
 
   // Dispatch odd char messages which are caused by ATOK or WXG (both of them
   // are Japanese IME) and removed by RemoveFollowingOddCharMessages().
-  for (size_t i = 0; i < mRemovedOddCharMsgs.Length(); ++i) {
+  for (size_t i = 0;
+       i < mRemovedOddCharMsgs.Length() && mWidget->ShouldDispatchPluginEvent();
+       ++i) {
     MOZ_RELEASE_ASSERT(!mWidget->Destroyed(),
       "NativeKey tries to dispatch a plugin event on destroyed widget");
     mWidget->DispatchPluginEvent(mRemovedOddCharMsgs[i]);
diff --git a/widget/windows/KeyboardLayout.h b/widget/windows/KeyboardLayout.h
index 8a9c1d0e0c1d..a27319aa8b49 100644
--- a/widget/windows/KeyboardLayout.h
+++ b/widget/windows/KeyboardLayout.h
@@ -504,12 +504,12 @@ private:
   bool DispatchKeyPressEventsWithoutCharMessage() const;
 
   /**
-   * Remove all following WM_CHAR, WM_SYSCHAR and WM_DEADCHAR messages for the
-   * WM_KEYDOWN or WM_SYSKEYDOWN message.  Additionally, dispatches plugin
-   * events if it's necessary.
-   * Returns true if the widget is destroyed.  Otherwise, false.
+   * MaybeDispatchPluginEventsForRemovedCharMessages() dispatches plugin events
+   * for removed char messages when a windowless plugin has focus.
+   * Returns true if the widget is destroyed or blurred during dispatching a
+   * plugin event.
    */
-  bool DispatchPluginEventsAndDiscardsCharMessages() const;
+  bool MaybeDispatchPluginEventsForRemovedCharMessages() const;
 
   /**
    * DispatchKeyPressEventForFollowingCharMessage() dispatches keypress event
diff --git a/widget/windows/nsWindowBase.cpp b/widget/windows/nsWindowBase.cpp
index da4c6c2c2edb..4c2edac6e527 100644
--- a/widget/windows/nsWindowBase.cpp
+++ b/widget/windows/nsWindowBase.cpp
@@ -21,7 +21,7 @@ InjectTouchInputPtr nsWindowBase::sInjectTouchFuncPtr;
 bool
 nsWindowBase::DispatchPluginEvent(const MSG& aMsg)
 {
-  if (!PluginHasFocus()) {
+  if (!ShouldDispatchPluginEvent()) {
     return false;
   }
   WidgetPluginEvent pluginEvent(true, ePluginInputEvent, this);
@@ -36,6 +36,12 @@ nsWindowBase::DispatchPluginEvent(const MSG& aMsg)
   return DispatchWindowEvent(&pluginEvent);
 }
 
+bool
+nsWindowBase::ShouldDispatchPluginEvent()
+{
+  return PluginHasFocus();
+}
+
 // static
 bool
 nsWindowBase::InitTouchInjection()
diff --git a/widget/windows/nsWindowBase.h b/widget/windows/nsWindowBase.h
index 46b237f4a1a5..405f5b359ea2 100644
--- a/widget/windows/nsWindowBase.h
+++ b/widget/windows/nsWindowBase.h
@@ -85,6 +85,11 @@ public:
    */
   virtual bool DispatchPluginEvent(const MSG& aMsg);
 
+  /*
+   * Returns true if this should dispatch a plugin event.
+   */
+  bool ShouldDispatchPluginEvent();
+
   /*
    * Touch input injection apis
    */