--- a/widget/windows/KeyboardLayout.cpp
+++ b/widget/windows/KeyboardLayout.cpp
@@ -856,17 +856,16 @@ NativeKey::NativeKey(nsWindowBase* aWidg
   , mModKeyState(aModKeyState)
   , mVirtualKeyCode(0)
   , mOriginalVirtualKeyCode(0)
   , mShiftedLatinChar(0)
   , mUnshiftedLatinChar(0)
   , mScanCode(0)
   , mIsExtended(false)
   , mIsDeadKey(false)
-  , mIsFollowedByNonControlCharMessage(false)
   , mFakeCharMsgs(aFakeCharMsgs && aFakeCharMsgs->Length() ?
                     aFakeCharMsgs : nullptr)
 {
   MOZ_ASSERT(aWidget);
   MOZ_ASSERT(mDispatcher);
   KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
   mKeyboardLayout = keyboardLayout->GetLayout();
   if (aOverrideKeyboardLayout && mKeyboardLayout != aOverrideKeyboardLayout) {
@@ -1056,19 +1055,19 @@ NativeKey::NativeKey(nsWindowBase* aWidg
   if (!mVirtualKeyCode) {
     mVirtualKeyCode = mOriginalVirtualKeyCode;
   }
 
   mDOMKeyCode =
     keyboardLayout->ConvertNativeKeyCodeToDOMKeyCode(mOriginalVirtualKeyCode);
   // Be aware, keyboard utilities can change non-printable keys to printable
   // keys.  In such case, we should make the key value as a printable key.
-  mIsFollowedByNonControlCharMessage =
-    IsKeyDownMessage() && IsFollowedByNonControlCharMessage();
-  mKeyNameIndex = mIsFollowedByNonControlCharMessage ?
+  // FYI: IsFollowedByNonControlCharMessage() returns true only when it's
+  //      handling a keydown message.
+  mKeyNameIndex = IsFollowedByNonControlCharMessage() ?
     KEY_NAME_INDEX_USE_STRING :
     keyboardLayout->ConvertNativeKeyCodeToKeyNameIndex(mOriginalVirtualKeyCode);
   mCodeNameIndex =
     KeyboardLayout::ConvertScanCodeToCodeNameIndex(
       GetScanCodeWithExtendedFlag());
 
   keyboardLayout->InitNativeKey(*this, mModKeyState);
 
@@ -2033,17 +2032,17 @@ NativeKey::NeedsToHandleWithoutFollowing
   // whole following char messages.
   if (mCommittedCharsAndModifiers.mLength > 1) {
     return true;
   }
 
   // If keydown message is followed by WM_CHAR whose wParam isn't a control
   // character, we should dispatch keypress event with the char message
   // even with any modifier state.
-  if (mIsFollowedByNonControlCharMessage) {
+  if (IsFollowedByNonControlCharMessage()) {
     return false;
   }
 
   // If any modifier keys which may cause printable keys becoming non-printable
   // are not pressed, we don't need special handling for the key.
   if (!mModKeyState.IsControl() && !mModKeyState.IsAlt() &&
       !mModKeyState.IsWin()) {
     return false;

--- a/widget/windows/KeyboardLayout.h
+++ b/widget/windows/KeyboardLayout.h
@@ -316,20 +316,16 @@ private:
   // mIsPrintableKey is true if the key may be a printable key without
   // any modifier keys.  Otherwise, false.
   // Please note that the event may not cause any text input even if this
   // is true.  E.g., it might be dead key state or Ctrl key may be pressed.
   bool    mIsPrintableKey;
   // mIsOverridingKeyboardLayout is true if the instance temporarily overriding
   // keyboard layout with specified by the constructor.
   bool    mIsOverridingKeyboardLayout;
-  // mIsFollowedByNonControlCharMessage may be true when mMsg is a keydown
-  // message.  When the keydown message is followed by a char message, this
-  // is true.
-  bool    mIsFollowedByNonControlCharMessage;
 
   nsTArray<FakeCharMsg>* mFakeCharMsgs;
 
   // When a keydown event is dispatched at handling WM_APPCOMMAND, the computed
   // virtual keycode is set to this.  Even if we consume WM_APPCOMMAND message,
   // Windows may send WM_KEYDOWN and WM_KEYUP message for them.
   // At that time, we should not dispatch key events for them.
   static uint8_t sDispatchedKeyOfAppCommand;