diff --git a/src/Text3.cpp b/src/Text3.cpp
index 5a84381b49..18e915f6af 100644
--- a/src/Text3.cpp
+++ b/src/Text3.cpp
@@ -1586,6 +1586,7 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 	}
 
 	needsUpdate |= (cur.pos() != cur.lastpos()) && cur.selection();
+	theSelection().haveSelection(bv->cursor().selection());
 
 	// FIXME: The cursor flag is reset two lines below
 	// so we need to check here if some of the LFUN did touch that.
diff --git a/src/frontends/qt4/QDocument.cpp b/src/frontends/qt4/QDocument.cpp
index ca514aab13..baa3fad82e 100644
--- a/src/frontends/qt4/QDocument.cpp
+++ b/src/frontends/qt4/QDocument.cpp
@@ -225,9 +225,9 @@ QDocumentDialog::QDocumentDialog(QDocument * form)
 	connect(textLayoutModule->bypassCB, SIGNAL(clicked()), 
 		this, SLOT(change_adaptor()));
 	connect(textLayoutModule->bypassCB, SIGNAL(clicked()), 
-		this, SLOT(validate_listings_params()));
+		this, SLOT(set_listings_msg()));
 	connect(textLayoutModule->listingsED, SIGNAL(textChanged()),
-		this, SLOT(validate_listings_params()));
+		this, SLOT(set_listings_msg()));
 	textLayoutModule->listingsTB->setPlainText(
 		qt_("Input listings parameters on the right. Enter ? for a list of parameters."));
 	textLayoutModule->lspacingLE->setValidator(new QDoubleValidator(
@@ -623,13 +623,29 @@ void QDocumentDialog::change_adaptor()
 }
 
 
-void QDocumentDialog::validate_listings_params()
+docstring QDocumentDialog::validate_listings_params()
+{
+	// use a cache here to avoid repeated validation
+	// of the same parameters
+	static string param_cache = string();
+	static docstring msg_cache = docstring();
+	
+	if (textLayoutModule->bypassCB->isChecked())
+		return docstring();
+
+	string params = fromqstr(textLayoutModule->listingsED->toPlainText());
+	if (params != param_cache) {
+		param_cache = params;
+		msg_cache = InsetListingsParams(params).validate();
+	}
+	return msg_cache;
+}
+
+
+void QDocumentDialog::set_listings_msg()
 {
 	static bool isOK = true;
-	InsetListingsParams par(fromqstr(textLayoutModule->listingsED->toPlainText()));
-	docstring msg;
-	if (!textLayoutModule->bypassCB->isChecked())
-		msg = par.validate();
+	docstring msg = validate_listings_params();
 	if (msg.empty()) {
 		if (isOK)
 			return;
@@ -637,14 +653,10 @@ void QDocumentDialog::validate_listings_params()
 		// listingsTB->setTextColor("black");
 		textLayoutModule->listingsTB->setPlainText(
 			qt_("Input listings parameters on the right. Enter ? for a list of parameters."));
-		okPB->setEnabled(true);
-		applyPB->setEnabled(true);
 	} else {
 		isOK = false;
 		// listingsTB->setTextColor("red");
 		textLayoutModule->listingsTB->setPlainText(toqstr(msg));
-		okPB->setEnabled(false);
-		applyPB->setEnabled(false);
 	}
 }
 
@@ -1449,6 +1461,13 @@ void QDocument::useClassDefaults()
 	update_contents();
 }
 
+
+bool QDocument::isValid()
+{
+	return dialog_->validate_listings_params().empty();
+}
+
+
 } // namespace frontend
 } // namespace lyx
 
diff --git a/src/frontends/qt4/QDocument.h b/src/frontends/qt4/QDocument.h
index 58a1754bc5..113c57c0b6 100644
--- a/src/frontends/qt4/QDocument.h
+++ b/src/frontends/qt4/QDocument.h
@@ -68,11 +68,13 @@ public:
 	void updatePagestyle(std::string const &, std::string const &);
 
 	void showPreamble();
+	/// validate listings parameters and return an error message, if any
+	docstring validate_listings_params();
 
 public Q_SLOTS:
 	void updateNumbering();
 	void change_adaptor();
-	void validate_listings_params();
+	void set_listings_msg();
 	void saveDefaultClicked();
 	void useDefaultsClicked();
 
@@ -141,6 +143,9 @@ private:
 	void saveDocDefault();
 	/// reset to default params
 	void useClassDefaults();
+protected:
+	/// return false if validate_listings_params returns error
+	virtual bool isValid();
 };
 
 
diff --git a/src/frontends/qt4/QInclude.cpp b/src/frontends/qt4/QInclude.cpp
index c4f650f4b6..9908edd344 100644
--- a/src/frontends/qt4/QInclude.cpp
+++ b/src/frontends/qt4/QInclude.cpp
@@ -64,9 +64,9 @@ QIncludeDialog::QIncludeDialog(QInclude * form)
 	connect(captionLE, SIGNAL(textChanged(const QString&)), this, SLOT(change_adaptor()));
 	connect(labelLE, SIGNAL(textChanged(const QString&)), this, SLOT(change_adaptor()));
 	connect(listingsED, SIGNAL(textChanged()), this, SLOT(change_adaptor()));
-	connect(listingsED, SIGNAL(textChanged()), this, SLOT(validate_listings_params()));
+	connect(listingsED, SIGNAL(textChanged()), this, SLOT(set_listings_msg()));
 	connect(bypassCB, SIGNAL(clicked()), this, SLOT(change_adaptor()));
-	connect(bypassCB, SIGNAL(clicked()), this, SLOT(validate_listings_params()));
+	connect(bypassCB, SIGNAL(clicked()), this, SLOT(set_listings_msg()));
 
 	setFocusProxy(filenameED);
 }
@@ -84,24 +84,38 @@ void QIncludeDialog::change_adaptor()
 }
 
 
-void QIncludeDialog::validate_listings_params()
+docstring QIncludeDialog::validate_listings_params()
+{
+	// use a cache here to avoid repeated validation
+	// of the same parameters
+	static string param_cache = string();
+	static docstring msg_cache = docstring();
+	
+	if (typeCO->currentIndex() != 3 || bypassCB->isChecked())
+		return docstring();
+
+	string params = fromqstr(listingsED->toPlainText());
+	if (params != param_cache) {
+		param_cache = params;
+		msg_cache = InsetListingsParams(params).validate();
+	}
+	return msg_cache;
+}
+
+
+void QIncludeDialog::set_listings_msg()
 {
 	static bool isOK = true;
-	InsetListingsParams par(fromqstr(listingsED->toPlainText()));
-	docstring msg;
-	if (!bypassCB->isChecked())
-		msg = par.validate();
+	docstring msg = validate_listings_params();
 	if (msg.empty()) {
 		if (isOK)
 			return;
 		isOK = true;
 		listingsTB->setPlainText(
 			qt_("Input listing parameters on the right. Enter ? for a list of parameters."));
-		okPB->setEnabled(true);
 	} else {
 		isOK = false;
 		listingsTB->setPlainText(toqstr(msg));
-		okPB->setEnabled(false);
 	}
 }
 
@@ -334,7 +348,8 @@ void QInclude::load()
 
 bool QInclude::isValid()
 {
-	return !dialog_->filenameED->text().isEmpty();
+	return !dialog_->filenameED->text().isEmpty() &&
+		dialog_->validate_listings_params().empty();
 }
 
 } // namespace frontend
diff --git a/src/frontends/qt4/QInclude.h b/src/frontends/qt4/QInclude.h
index bc7244058d..6d4a3ba09f 100644
--- a/src/frontends/qt4/QInclude.h
+++ b/src/frontends/qt4/QInclude.h
@@ -31,12 +31,18 @@ public:
 	void updateLists();
 
 	virtual void show();
+	/// validate listings parameters and return an error message, if any
+	docstring validate_listings_params();
 protected Q_SLOTS:
 	virtual void change_adaptor();
-	void validate_listings_params();
 	virtual void loadClicked();
 	virtual void browseClicked();
 	virtual void typeChanged(int v);
+	/// AFAIK, QValidator only works for QLineEdit so
+	/// I have to validate listingsED (QTextEdit) manually.
+	/// This function displays a hint or error message returned by
+	/// validate_listings_params
+	void set_listings_msg();
 protected:
 	virtual void closeEvent(QCloseEvent * e);
 private:
diff --git a/src/frontends/qt4/QListings.cpp b/src/frontends/qt4/QListings.cpp
index 67be99fb58..373eba9e37 100644
--- a/src/frontends/qt4/QListings.cpp
+++ b/src/frontends/qt4/QListings.cpp
@@ -190,9 +190,9 @@ QListingsDialog::QListingsDialog(QListings * form)
 	connect(extendedcharsCB, SIGNAL(clicked()), this, SLOT(change_adaptor()));
 
 	connect(listingsED,  SIGNAL(textChanged()), this, SLOT(change_adaptor()));
-	connect(listingsED,  SIGNAL(textChanged()), this, SLOT(validate_listings_params()));
+	connect(listingsED,  SIGNAL(textChanged()), this, SLOT(set_listings_msg()));
 	connect(bypassCB, SIGNAL(clicked()), this, SLOT(change_adaptor()));
-	connect(bypassCB, SIGNAL(clicked()), this, SLOT(validate_listings_params()));
+	connect(bypassCB, SIGNAL(clicked()), this, SLOT(set_listings_msg()));
 
 	for (int n = 0; languages[n][0]; ++n)
 		languageCO->addItem(qt_(languages_gui[n]));
@@ -319,26 +319,38 @@ string QListingsDialog::construct_params()
 }
 
 
-void QListingsDialog::validate_listings_params()
+docstring QListingsDialog::validate_listings_params()
+{
+	// use a cache here to avoid repeated validation
+	// of the same parameters
+	static string param_cache = string();
+	static docstring msg_cache = docstring();
+	
+	if (bypassCB->isChecked())
+		return docstring();
+
+	string params = construct_params();
+	if (params != param_cache) {
+		param_cache = params;
+		msg_cache = InsetListingsParams(params).validate();
+	}
+	return msg_cache;
+}
+
+
+void QListingsDialog::set_listings_msg()
 {
 	static bool isOK = true;
-	InsetListingsParams par(construct_params());
-	docstring msg;
-	if (!bypassCB->isChecked())
-		msg = par.validate();
+	docstring msg = validate_listings_params();
 	if (msg.empty()) {
 		if (isOK)
 			return;
 		isOK = true;
 		listingsTB->setPlainText(
 			qt_("Input listing parameters on the right. Enter ? for a list of parameters."));
-		okPB->setEnabled(true);
-		applyPB->setEnabled(true);
 	} else {
 		isOK = false;
 		listingsTB->setPlainText(toqstr(msg));
-		okPB->setEnabled(false);
-		applyPB->setEnabled(false);
 	}
 }
 
@@ -601,6 +613,12 @@ void QListings::update_contents()
 }
 
 
+bool QListings::isValid()
+{
+	return dialog_->validate_listings_params().empty();
+}
+
+
 } // namespace frontend
 } // namespace lyx
 
diff --git a/src/frontends/qt4/QListings.h b/src/frontends/qt4/QListings.h
index 134df30636..730efccc42 100644
--- a/src/frontends/qt4/QListings.h
+++ b/src/frontends/qt4/QListings.h
@@ -29,11 +29,15 @@ public:
 	QListingsDialog(QListings * form);
 	/// get values from all the widgets and form a string
 	std::string construct_params();
+	/// validate listings parameters and return an error message, if any
+	docstring validate_listings_params();
 protected Q_SLOTS:
 	virtual void change_adaptor();
 	/// AFAIK, QValidator only works for QLineEdit so
 	/// I have to validate listingsED (QTextEdit) manually.
-	void validate_listings_params();
+	/// This function displays a hint or error message returned by
+	/// validate_listings_params
+	void set_listings_msg();
 	/// turn off inline when float is clicked
 	void on_floatCB_stateChanged(int state);
 	/// turn off float when inline is clicked
@@ -63,6 +67,9 @@ private:
 	virtual void update_contents();
 	/// build the dialog
 	virtual void build_dialog();
+protected:
+	/// return false if validate_listings_params returns error
+	virtual bool isValid();
 };
 
 } // namespace frontend
diff --git a/src/insets/InsetTabular.cpp b/src/insets/InsetTabular.cpp
index d2545eea34..3cc40d46bd 100644
--- a/src/insets/InsetTabular.cpp
+++ b/src/insets/InsetTabular.cpp
@@ -3490,6 +3490,7 @@ void InsetTabular::doDispatch(Cursor & cur, FuncRequest & cmd)
 		cell(cur.idx())->dispatch(cur, cmd);
 		break;
 	}
+	theSelection().haveSelection(bvcur.selection());
 }