diff --git a/mainwindow.cpp b/mainwindow.cpp
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -36,6 +36,11 @@
 #include "version.h"
 #include "floatswap.h"
 
+#if defined(Q_OS_WIN) && defined(QT_STATIC)
+#include <QtPlugin>
+Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin)
+#endif
+
 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
     ui(new Ui::MainWindow),
@@ -56,6 +61,9 @@ MainWindow::MainWindow(QWidget *parent) 
     QObject::connect(ui->actionExportCsv, &QAction::triggered,
                      this, &MainWindow::onExportCsv);
 
+    QObject::connect(ui->actionQuit, &QAction::triggered,
+                     this, &MainWindow::close);
+
     QObject::connect(&portControl, &PortControl::portToggled,
                      this, &MainWindow::onPortToggled);
 
@@ -137,6 +145,7 @@ MainWindow::MainWindow(QWidget *parent) 
         selectNumberFormat(NumberFormat_uint8);
     }
 
+
     // init text view
     ui->ptTextView->setEnabled(ui->cbEnableTextView->isChecked());
     // TODO: does this work in binary mode? (no new lines)
@@ -146,6 +155,16 @@ MainWindow::MainWindow(QWidget *parent) 
     QObject::connect(ui->pbClearTextView, &QPushButton::clicked,
                      ui->ptTextView, &QPlainTextEdit::clear);
 
+
+    // Init sps (sample per second) counter
+    sampleCount = 0;
+    spsLabel.setText("0sps");
+    spsLabel.setToolTip("samples per second (total of all channels)");
+    ui->statusBar->addPermanentWidget(&spsLabel);
+    spsTimer.start(SPS_UPDATE_TIMEOUT * 1000);
+    QObject::connect(&spsTimer, &QTimer::timeout,
+                     this, &MainWindow::spsTimerTimeout);
+
     // Init demo mode
     demoCount = 0;
     demoTimer.setInterval(100);
@@ -153,6 +172,18 @@ MainWindow::MainWindow(QWidget *parent) 
                      this, &MainWindow::demoTimerTimeout);
     QObject::connect(ui->actionDemoMode, &QAction::toggled,
                      this, &MainWindow::enableDemo);
+
+    {   // init demo indicator
+        QwtText demoText(" DEMO RUNNING ");  // looks better with spaces
+        demoText.setColor(QColor("white"));
+        demoText.setBackgroundBrush(Qt::darkRed);
+        demoText.setBorderRadius(4);
+        demoText.setRenderFlags(Qt::AlignLeft | Qt::AlignTop);
+        demoIndicator.setText(demoText);
+        demoIndicator.hide();
+        demoIndicator.attach(ui->plot);
+    }
+
 }
 
 MainWindow::~MainWindow()
@@ -246,6 +277,13 @@ void MainWindow::onDataReadyASCII()
     while(serialPort.canReadLine())
     {
         QByteArray line = serialPort.readLine();
+
+        // discard data if paused
+        if (ui->actionPause->isChecked())
+        {
+            return;
+        }
+
         line = line.trimmed();
 
         if (ui->cbEnableTextView->isChecked())
@@ -372,6 +410,8 @@ void MainWindow::addChannelData(unsigned
     // update plot
     curves[channel]->setSamples(dataX, (*channelDataArray));
     ui->plot->replot(); // TODO: replot after all channel data updated
+
+    sampleCount += data.size();
 }
 
 void MainWindow::clearPlot()
@@ -564,6 +604,12 @@ bool MainWindow::isDemoRunning()
     return ui->actionDemoMode->isChecked();
 }
 
+void MainWindow::spsTimerTimeout()
+{
+    spsLabel.setText(QString::number(sampleCount/SPS_UPDATE_TIMEOUT) + "sps");
+    sampleCount = 0;
+}
+
 void MainWindow::demoTimerTimeout()
 {
     demoCount++;
@@ -588,6 +634,8 @@ void MainWindow::enableDemo(bool enabled
         {
             demoTimer.start();
             ui->actionDemoMode->setChecked(true);
+            demoIndicator.show();
+            ui->plot->replot();
         }
         else
         {
@@ -598,6 +646,8 @@ void MainWindow::enableDemo(bool enabled
     {
         demoTimer.stop();
         ui->actionDemoMode->setChecked(false);
+        demoIndicator.hide();
+        ui->plot->replot();
     }
 }