diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index fe2646acdf..625a424a72 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -3735,7 +3735,6 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			if (!doc_buffer->isClean()) {
 				docstring const file =
 					makeDisplayPath(doc_buffer->absFileName(), 20);
-				doc_buffer->notifiesExternalModification();
 				docstring text = doc_buffer->notifiesExternalModification() ?
 					  _("Any changes will be lost. "
 					    "Are you sure you want to load the version on disk "
diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index 67d94942da..b87bb48f4c 100644
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -1683,35 +1683,41 @@ void TabWorkArea::showBar(bool show)
 }
 
 
-GuiWorkArea * TabWorkArea::currentWorkArea()
+GuiWorkAreaContainer * TabWorkArea::widget(int index) const
 {
-	if (count() == 0)
-		return 0;
-
-	GuiWorkAreaContainer * wac =
-		dynamic_cast<GuiWorkAreaContainer *>(currentWidget());
+	QWidget * w = QTabWidget::widget(index);
+	if (!w)
+		return nullptr;
+	GuiWorkAreaContainer * wac = dynamic_cast<GuiWorkAreaContainer *>(w);
 	LATTEST(wac);
-	GuiWorkArea * wa = wac->workArea();
-	LATTEST(wa);
-	return wa;
+	return wac;
 }
 
 
-GuiWorkArea const * TabWorkArea::workArea(int index) const
+GuiWorkAreaContainer * TabWorkArea::currentWidget() const
 {
-	return (dynamic_cast<GuiWorkAreaContainer *>(widget(index)))->workArea();
+	return widget(currentIndex());
 }
 
 
-GuiWorkArea * TabWorkArea::workArea(int index)
+GuiWorkArea * TabWorkArea::workArea(int index) const
 {
-	return (dynamic_cast<GuiWorkAreaContainer *>(widget(index)))->workArea();
+	GuiWorkAreaContainer * w = widget(index);
+	if (!w)
+		return nullptr;
+	return w->workArea();
 }
 
 
-GuiWorkArea * TabWorkArea::workArea(Buffer & buffer)
+GuiWorkArea * TabWorkArea::currentWorkArea() const
 {
-	// FIXME: this method doesn't work if we have more than work area
+	return workArea(currentIndex());
+}
+
+
+GuiWorkArea * TabWorkArea::workArea(Buffer & buffer) const
+{
+	// FIXME: this method doesn't work if we have more than one work area
 	// showing the same buffer.
 	for (int i = 0; i != count(); ++i) {
 		GuiWorkArea * wa = workArea(i);
@@ -2220,9 +2226,6 @@ GuiWorkAreaContainer::GuiWorkAreaContainer(GuiWorkArea * wa, QWidget * parent)
 
 void GuiWorkAreaContainer::updateDisplay()
 {
-	if (!wa_)
-		notificationFrame->hide();
-
 	Buffer const & buf = wa_->bufferView().buffer();
 	notificationFrame->setHidden(!buf.notifiesExternalModification());
 	QString const label = QString("<b>The file \"%1\" changed on disk.</b>")
@@ -2233,8 +2236,6 @@ void GuiWorkAreaContainer::updateDisplay()
 
 void GuiWorkAreaContainer::dispatch(FuncRequest f) const
 {
-	if (!wa_)
-		return;
 	lyx::dispatch(FuncRequest(LFUN_BUFFER_SWITCH,
 	                          wa_->bufferView().buffer().absFileName()));
 	lyx::dispatch(f);
diff --git a/src/frontends/qt4/GuiWorkArea.h b/src/frontends/qt4/GuiWorkArea.h
index aa407e13c0..b22d2a5662 100644
--- a/src/frontends/qt4/GuiWorkArea.h
+++ b/src/frontends/qt4/GuiWorkArea.h
@@ -193,6 +193,8 @@ private:
 }; // EmbeddedWorkArea
 
 
+class GuiWorkAreaContainer;
+
 /// A tabbed set of GuiWorkAreas.
 class TabWorkArea : public QTabWidget
 {
@@ -200,6 +202,10 @@ class TabWorkArea : public QTabWidget
 public:
 	TabWorkArea(QWidget * parent = 0);
 
+	/// hide QTabWidget methods
+	GuiWorkAreaContainer * currentWidget() const;
+	GuiWorkAreaContainer * widget(int index) const;
+
 	///
 	void setFullScreen(bool full_screen);
 	void showBar(bool show);
@@ -207,10 +213,9 @@ public:
 	bool setCurrentWorkArea(GuiWorkArea *);
 	GuiWorkArea * addWorkArea(Buffer & buffer, GuiView & view);
 	bool removeWorkArea(GuiWorkArea *);
-	GuiWorkArea * currentWorkArea();
-	GuiWorkArea * workArea(Buffer & buffer);
-	GuiWorkArea const * workArea(int index) const;
-	GuiWorkArea * workArea(int index);
+	GuiWorkArea * currentWorkArea() const;
+	GuiWorkArea * workArea(Buffer & buffer) const;
+	GuiWorkArea * workArea(int index) const;
 	void paintEvent(QPaintEvent *);
 
 Q_SIGNALS:
@@ -230,7 +235,7 @@ public Q_SLOTS:
 	void moveTab(int fromIndex, int toIndex);
 	///
 	void updateTabTexts();
-	
+
 private Q_SLOTS:
 	///
 	void on_currentTabChanged(int index);
@@ -245,6 +250,9 @@ private Q_SLOTS:
 	int indexOfWorkArea(GuiWorkArea * w) const;
 
 private:
+	using QTabWidget::addTab;
+	using QTabWidget::insertTab;
+
 	/// true if position is a tab (rather than the blank space in tab bar)
 	bool posIsTab(QPoint position);
 
@@ -286,6 +294,7 @@ Q_SIGNALS:
 class GuiWorkAreaContainer : public QWidget, public Ui::WorkAreaUi
 {
 	Q_OBJECT
+	// non-null
 	GuiWorkArea * const wa_;
 	void dispatch(FuncRequest f) const;
 
@@ -298,8 +307,9 @@ protected:
 	void mouseDoubleClickEvent(QMouseEvent * event); //override
 
 public:
-	///
+	/// wa != 0
 	GuiWorkAreaContainer(GuiWorkArea * wa, QWidget * parent = 0);
+	/// non-null
 	GuiWorkArea * workArea() const { return wa_; }
 };