diff --git a/guilib/include/rtabmap/gui/PreferencesDialog.h b/guilib/include/rtabmap/gui/PreferencesDialog.h
index 4ec95eda..f3f7224b 100644
--- a/guilib/include/rtabmap/gui/PreferencesDialog.h
+++ b/guilib/include/rtabmap/gui/PreferencesDialog.h
@@ -97,11 +97,12 @@ public:
 	virtual QString getIniFilePath() const;
 	void init();
 
+	// save stuff
+	void saveSettings();
 	void saveWindowGeometry(const QWidget * window);
 	void loadWindowGeometry(QWidget * window);
 	void saveMainWindowState(const QMainWindow * mainWindow);
 	void loadMainWindowState(QMainWindow * mainWindow, bool & maximized);
-
 	void saveWidgetState(const QWidget * widget);
 	void loadWidgetState(QWidget * widget);
 
@@ -207,7 +208,6 @@ signals:
 public slots:
 	void setInputRate(double value);
 	void setDetectionRate(double value);
-	void setHardThr(int value);
 	void setTimeLimit(float value);
 	void setSLAMMode(bool enabled);
 	void selectSourceImage(Src src = kSrcUndef, bool checked = true);
@@ -260,9 +260,11 @@ protected:
 	virtual bool readCoreSettings(const QString & filePath = QString());
 
 	virtual void writeSettings(const QString & filePath = QString());
-	virtual void writeGuiSettings(const QString & filePath = QString());
-	virtual void writeCameraSettings(const QString & filePath = QString());
-	virtual void writeCoreSettings(const QString & filePath = QString());
+	virtual void writeGuiSettings(const QString & filePath = QString()) const;
+	virtual void writeCameraSettings(const QString & filePath = QString()) const;
+	virtual void writeCoreSettings(const QString & filePath = QString()) const;
+
+	QString getTmpIniFilePath() const;
 
 private:
 	bool validateForm();
diff --git a/guilib/src/MainWindow.cpp b/guilib/src/MainWindow.cpp
index 541021be..9658211a 100644
--- a/guilib/src/MainWindow.cpp
+++ b/guilib/src/MainWindow.cpp
@@ -364,6 +364,11 @@ MainWindow::MainWindow(PreferencesDialog * prefDialog, QWidget * parent) :
 	qRegisterMetaType<rtabmap::ParametersMap>("rtabmap::ParametersMap");
 	connect(_preferencesDialog, SIGNAL(settingsChanged(rtabmap::ParametersMap)), this, SLOT(applyPrefSettings(rtabmap::ParametersMap)));
 	// config GUI modified
+	connect(_preferencesDialog, SIGNAL(settingsChanged(PreferencesDialog::PANEL_FLAGS)), this, SLOT(configGUIModified()));
+	if(prefDialog == 0)
+	{
+		connect(_preferencesDialog, SIGNAL(settingsChanged(rtabmap::ParametersMap)), this, SLOT(configGUIModified()));
+	}
 	connect(_ui->imageView_source, SIGNAL(configChanged()), this, SLOT(configGUIModified()));
 	connect(_ui->imageView_loopClosure, SIGNAL(configChanged()), this, SLOT(configGUIModified()));
 	connect(_ui->imageView_odometry, SIGNAL(configChanged()), this, SLOT(configGUIModified()));
@@ -492,7 +497,7 @@ void MainWindow::closeEvent(QCloseEvent* event)
 		{
 			QMessageBox::Button b=QMessageBox::question(this,
 					tr("RTAB-Map"),
-					tr("There are unsaved GUI changes. Save them?"),
+					tr("There are unsaved changes. Save them?"),
 					QMessageBox::Save | QMessageBox::Cancel | QMessageBox::Discard);
 			if(b == QMessageBox::Save)
 			{
@@ -2252,6 +2257,7 @@ void MainWindow::saveConfigGUI()
 	_preferencesDialog->saveWidgetState(_exportDialog);
 	_preferencesDialog->saveWidgetState(_postProcessingDialog);
 	_preferencesDialog->saveWidgetState(_ui->graphicsView_graphView);
+	_preferencesDialog->saveSettings();
 	this->setWindowModified(false);
 }
 
diff --git a/guilib/src/PreferencesDialog.cpp b/guilib/src/PreferencesDialog.cpp
index 0d961ea0..0c3e99a0 100644
--- a/guilib/src/PreferencesDialog.cpp
+++ b/guilib/src/PreferencesDialog.cpp
@@ -545,6 +545,8 @@ PreferencesDialog::PreferencesDialog(QWidget * parent) :
 }
 
 PreferencesDialog::~PreferencesDialog() {
+	// remove tmp ini file
+	QFile::remove(getTmpIniFilePath());
 	delete _ui;
 }
 
@@ -558,11 +560,16 @@ void PreferencesDialog::init()
 	}
 
 	this->readSettings();
-	this->writeSettings();// This will create the ini file if not exist
+	this->writeSettings(getTmpIniFilePath());
 
 	_initialized = true;
 }
 
+void PreferencesDialog::saveSettings()
+{
+	writeSettings();
+}
+
 void PreferencesDialog::setupTreeView()
 {
 	if(_indexModel)
@@ -753,6 +760,8 @@ void PreferencesDialog::closeEvent(QCloseEvent *event)
 	UDEBUG("");
 	_parameters.clear();
 	_obsoletePanels = kPanelDummy;
+	this->readGuiSettings(getTmpIniFilePath());
+	this->readCameraSettings(getTmpIniFilePath());
 	event->accept();
 }
 
@@ -766,6 +775,8 @@ void PreferencesDialog::closeDialog ( QAbstractButton * button )
 	case QDialogButtonBox::RejectRole:
 		_parameters.clear();
 		_obsoletePanels = kPanelDummy;
+		this->readGuiSettings(getTmpIniFilePath());
+		this->readCameraSettings(getTmpIniFilePath());
 		this->reject();
 		break;
 
@@ -775,7 +786,7 @@ void PreferencesDialog::closeDialog ( QAbstractButton * button )
 		{
 			if(validateForm())
 			{
-				writeSettings();
+				writeSettings(getTmpIniFilePath());
 				this->accept();
 			}
 		}
@@ -799,7 +810,7 @@ void PreferencesDialog::resetApply ( QAbstractButton * button )
 		updateBasicParameter();// make that changes without editing finished signal are updated.
 		if(validateForm())
 		{
-			writeSettings();
+			writeSettings(getTmpIniFilePath());
 		}
 		break;
 
@@ -995,6 +1006,11 @@ QString PreferencesDialog::getIniFilePath() const
 	return privatePath + "/rtabmap.ini";
 }
 
+QString PreferencesDialog::getTmpIniFilePath() const
+{
+	return getIniFilePath()+".tmp";
+}
+
 void PreferencesDialog::loadConfigFrom()
 {
 	QString path = QFileDialog::getOpenFileName(this, tr("Load settings..."), this->getWorkingDirectory(), "*.ini");
@@ -1246,7 +1262,9 @@ bool PreferencesDialog::saveConfigTo()
 	QString path = QFileDialog::getSaveFileName(this, tr("Save settings..."), this->getWorkingDirectory()+QDir::separator()+"config.ini", "*.ini");
 	if(!path.isEmpty())
 	{
-		this->writeSettings(path);
+		writeGuiSettings(path);
+		writeCameraSettings(path);
+		writeCoreSettings(path);
 		return true;
 	}
 	return false;
@@ -1288,7 +1306,7 @@ void PreferencesDialog::writeSettings(const QString & filePath)
 	_obsoletePanels = kPanelDummy;
 }
 
-void PreferencesDialog::writeGuiSettings(const QString & filePath)
+void PreferencesDialog::writeGuiSettings(const QString & filePath) const
 {
 	QString path = getIniFilePath();
 	if(!filePath.isEmpty())
@@ -1346,7 +1364,7 @@ void PreferencesDialog::writeGuiSettings(const QString & filePath)
 	settings.endGroup(); // rtabmap
 }
 
-void PreferencesDialog::writeCameraSettings(const QString & filePath)
+void PreferencesDialog::writeCameraSettings(const QString & filePath) const
 {
 	QString path = getIniFilePath();
 	if(!filePath.isEmpty())
@@ -1404,7 +1422,7 @@ void PreferencesDialog::writeCameraSettings(const QString & filePath)
 	settings.endGroup();
 }
 
-void PreferencesDialog::writeCoreSettings(const QString & filePath)
+void PreferencesDialog::writeCoreSettings(const QString & filePath) const
 {
 	QString path = getIniFilePath();
 	if(!filePath.isEmpty())
@@ -1611,7 +1629,7 @@ void PreferencesDialog::readSettingsEnd()
 {
 	QApplication::processEvents();
 
-	this->readSettings();
+	this->readSettings(getTmpIniFilePath());
 
 	_progressDialog->setValue(1);
 	if(this->isVisible())
@@ -2026,7 +2044,7 @@ void PreferencesDialog::selectSourceImage(Src src, bool ckecked)
 
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
@@ -2077,7 +2095,7 @@ void PreferencesDialog::selectSourceDatabase(bool user, bool ckecked)
 
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
@@ -2144,7 +2162,7 @@ void PreferencesDialog::selectSourceRGBD(Src src, bool ckecked)
 		// Even if there is no change, MainWindow should be notified
 		makeObsoleteSourcePanel();
 
-		this->writeSettings();
+		this->writeSettings(getTmpIniFilePath());
 	}
 	else
 	{
@@ -3210,24 +3228,6 @@ bool PreferencesDialog::isSLAMMode() const
 }
 
 /*** SETTERS ***/
-void PreferencesDialog::setHardThr(int value)
-{
-	double dValue = double(value)/100;
-	ULOGGER_DEBUG("PreferencesDialog::setHardThr(%f)", dValue);
-	if(_ui->general_doubleSpinBox_hardThr->value() != dValue)
-	{
-		_ui->general_doubleSpinBox_hardThr->setValue(dValue);
-		if(validateForm())
-		{
-			this->writeSettings();
-		}
-		else
-		{
-			this->readSettingsBegin();
-		}
-	}
-}
-
 void PreferencesDialog::setInputRate(double value)
 {
 	ULOGGER_DEBUG("imgRate=%2.2f", value);
@@ -3236,7 +3236,7 @@ void PreferencesDialog::setInputRate(double value)
 		_ui->general_doubleSpinBox_imgRate->setValue(value);
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
@@ -3253,7 +3253,7 @@ void PreferencesDialog::setDetectionRate(double value)
 		_ui->general_doubleSpinBox_detectionRate->setValue(value);
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
@@ -3270,7 +3270,7 @@ void PreferencesDialog::setTimeLimit(float value)
 		_ui->general_doubleSpinBox_timeThr->setValue(value);
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
@@ -3287,7 +3287,7 @@ void PreferencesDialog::setSLAMMode(bool enabled)
 		_ui->general_checkBox_SLAM_mode->setChecked(enabled);
 		if(validateForm())
 		{
-			this->writeSettings();
+			this->writeSettings(getTmpIniFilePath());
 		}
 		else
 		{
diff --git a/guilib/src/ui/mainWindow.ui b/guilib/src/ui/mainWindow.ui
index 7aba5432..a5d04de4 100644
--- a/guilib/src/ui/mainWindow.ui
+++ b/guilib/src/ui/mainWindow.ui
@@ -37,6 +37,8 @@
     <addaction name="actionNew_database"/>
     <addaction name="actionOpen_database"/>
     <addaction name="separator"/>
+    <addaction name="actionSave_GUI_config"/>
+    <addaction name="separator"/>
     <addaction name="actionSave_point_cloud"/>
     <addaction name="actionExport_2D_scans_ply_pcd"/>
     <addaction name="actionExport_2D_Grid_map_bmp_png"/>
@@ -178,7 +180,6 @@
      <addaction name="action360p"/>
      <addaction name="action240p"/>
     </widget>
-    <addaction name="actionSave_GUI_config"/>
     <addaction name="menuShow_view"/>
     <addaction name="menuFigures"/>
     <addaction name="actionScreenshot"/>
@@ -1119,7 +1120,7 @@
   </action>
   <action name="actionSave_GUI_config">
    <property name="text">
-    <string>Save GUI config</string>
+    <string>Save config</string>
    </property>
   </action>
  </widget>