diff --git a/dom/base/test/chrome/window_nsITextInputProcessor.xul b/dom/base/test/chrome/window_nsITextInputProcessor.xul
index e7efc44669b9..674bb348b1d9 100644
--- a/dom/base/test/chrome/window_nsITextInputProcessor.xul
+++ b/dom/base/test/chrome/window_nsITextInputProcessor.xul
@@ -157,7 +157,9 @@ function runBeginInputTransactionMethodTests()
   // Let's confirm that the composing string is NOT committed by above tests.
   TIP1.commitComposition();
   is(input.value, composingStr,
-     description + "TIP1.commitString() without specifying commit string should be committed with the last composing string");
+     description + "TIP1.commitString() without specifying commit string should commit current composition with the last composing string");
+  ok(!TIP1.hasComposition,
+     description + "TIP1.commitString() without specifying commit string should've end composition");
 
   ok(TIP1.beginInputTransaction(window, simpleCallback),
      description + "TIP1.beginInputTransaction() should succeed because there is no composition #2");
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index 1f517e1bdbac..be13838ee956 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -1933,6 +1933,22 @@ nsBaseWidget::EnsureTextEventDispatcher()
   mTextEventDispatcher = new TextEventDispatcher(this);
 }
 
+nsIWidget::NativeIMEContext
+nsBaseWidget::GetNativeIMEContext()
+{
+  if (mTextEventDispatcher && mTextEventDispatcher->GetPseudoIMEContext()) {
+    // If we already have a TextEventDispatcher and it's working with
+    // a TextInputProcessor, we need to return pseudo IME context since
+    // TextCompositionArray::IndexOf(nsIWidget*) should return a composition
+    // on the pseudo IME context in such case.
+    NativeIMEContext pseudoIMEContext;
+    pseudoIMEContext.InitWithRawNativeIMEContext(
+                       mTextEventDispatcher->GetPseudoIMEContext());
+    return pseudoIMEContext;
+  }
+  return NativeIMEContext(this);
+}
+
 nsIWidget::TextEventDispatcher*
 nsBaseWidget::GetTextEventDispatcher()
 {
@@ -2441,12 +2457,6 @@ nsBaseWidget::DefaultFillScrollCapture(DrawTarget* aSnapshotDrawTarget)
 }
 #endif
 
-nsIWidget::NativeIMEContext
-nsIWidget::GetNativeIMEContext()
-{
-  return NativeIMEContext(this);
-}
-
 const IMENotificationRequests&
 nsIWidget::IMENotificationRequestsRef()
 {
diff --git a/widget/nsBaseWidget.h b/widget/nsBaseWidget.h
index 606a5f336707..d9ebdb8bf2a1 100644
--- a/widget/nsBaseWidget.h
+++ b/widget/nsBaseWidget.h
@@ -298,6 +298,7 @@ public:
   virtual void               SetAttachedWidgetListener(nsIWidgetListener* aListener) override;
   virtual nsIWidgetListener* GetPreviouslyAttachedWidgetListener() override;
   virtual void               SetPreviouslyAttachedWidgetListener(nsIWidgetListener* aListener) override;
+  virtual NativeIMEContext GetNativeIMEContext() override;
   TextEventDispatcher* GetTextEventDispatcher() final;
   virtual TextEventDispatcherListener*
     GetNativeTextEventDispatcherListener() override;
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
index 03deae03070b..f8e2631dff74 100644
--- a/widget/nsIWidget.h
+++ b/widget/nsIWidget.h
@@ -1851,7 +1851,7 @@ public:
      * NS_RAW_NATIVE_IME_CONTEXT, the result is unique even if in a remote
      * process.
      */
-    virtual NativeIMEContext GetNativeIMEContext();
+    virtual NativeIMEContext GetNativeIMEContext() = 0;
 
     /*
      * Given a WidgetKeyboardEvent, this method synthesizes a corresponding