--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -586,16 +586,27 @@ nsWindow::Create(nsIWidget *aParent,
     else
       oldWndProc = (WNDPROC)::SetWindowLongPtrA(scrollableWnd, GWLP_WNDPROC,
                                                 (LONG_PTR)nsWindow::WindowProc);
     ::SetWindowLongPtrW(scrollableWnd, GWLP_USERDATA, (LONG_PTR)oldWndProc);
   }
 
   SubclassWindow(TRUE);
 
+  // NOTE: mNativeIMEContext may be null if IMM module isn't installed.
+  nsIMEContext IMEContext(mWnd);
+  mInputContext.mNativeIMEContext = static_cast<void*>(IMEContext.get());
+  MOZ_ASSERT(mInputContext.mNativeIMEContext ||
+             !nsIMM32Handler::IsIMEAvailable());
+  // If no IME context is available, we should set this widget's pointer since
+  // nullptr indicates there is only one context per process on the platform.
+  if (!mInputContext.mNativeIMEContext) {
+    mInputContext.mNativeIMEContext = this;
+  }
+
   // If the internal variable set by the config.trim_on_minimize pref has not
   // been initialized, and if this is the hidden window (conveniently created
   // before any visible windows, and after the profile has been initialized),
   // do some initialization work.
   if (sTrimOnMinimize == 2 && mWindowType == eWindowType_invisible) {
     // Our internal trim prevention logic is effective on 2K/XP at maintaining
     // the working set when windows are minimized, but on Vista and up it has
     // little to no effect. Since this feature has been the source of numerous
@@ -7283,22 +7294,33 @@ nsWindow::SetInputContext(const InputCon
                           const InputContextAction& aAction)
 {
 #ifdef NS_ENABLE_TSF
   nsTextStore::SetInputContext(aContext);
 #endif //NS_ENABLE_TSF
   if (nsIMM32Handler::IsComposing()) {
     ResetInputState();
   }
+  void* nativeIMEContext = mInputContext.mNativeIMEContext;
   mInputContext = aContext;
+  mInputContext.mNativeIMEContext = nullptr;
   bool enable = (mInputContext.mIMEState.mEnabled == IMEState::ENABLED ||
                  mInputContext.mIMEState.mEnabled == IMEState::PLUGIN);
 
   AssociateDefaultIMC(enable);
 
+  if (enable) {
+    nsIMEContext IMEContext(mWnd);
+    mInputContext.mNativeIMEContext = static_cast<void*>(IMEContext.get());
+  }
+  // Restore the latest associated context when we cannot get actual context.
+  if (!mInputContext.mNativeIMEContext) {
+    mInputContext.mNativeIMEContext = nativeIMEContext;
+  }
+
   if (enable &&
       mInputContext.mIMEState.mOpen != IMEState::DONT_CHANGE_OPEN_STATE) {
     bool open = (mInputContext.mIMEState.mOpen == IMEState::OPEN);
 #ifdef NS_ENABLE_TSF
     nsTextStore::SetIMEOpenState(open);
 #endif //NS_ENABLE_TSF
     nsIMEContext IMEContext(mWnd);
     if (IMEContext.IsValid()) {