diff --git a/DSView/pv/data/logicsnapshot.cpp b/DSView/pv/data/logicsnapshot.cpp
index 94918d08..16c7d026 100644
--- a/DSView/pv/data/logicsnapshot.cpp
+++ b/DSView/pv/data/logicsnapshot.cpp
@@ -532,6 +532,9 @@ bool LogicSnapshot::get_display_edges(std::vector<std::pair<bool, bool> > &edges
     if (_ring_sample_count == 0)
         return false;
 
+    if (_sample_count > _ring_sample_count)
+        dsv_info("_sample_count > _ring_sample_count");
+
     assert(end < _ring_sample_count);
     assert(start <= end);
     assert(min_length > 0);
diff --git a/DSView/pv/data/snapshot.cpp b/DSView/pv/data/snapshot.cpp
index 8558ea5c..a8d99d95 100644
--- a/DSView/pv/data/snapshot.cpp
+++ b/DSView/pv/data/snapshot.cpp
@@ -75,6 +75,12 @@ uint64_t Snapshot::get_sample_count()
     std::lock_guard<std::mutex> lock(_mutex);
     return _sample_count;
 }
+
+uint64_t Snapshot::get_ring_sample_count()
+{
+    std::lock_guard<std::mutex> lock(_mutex);
+    return _ring_sample_count;
+}
  
 uint64_t Snapshot::get_ring_start()
 {
diff --git a/DSView/pv/data/snapshot.h b/DSView/pv/data/snapshot.h
index e2ee9dbc..31c576d7 100644
--- a/DSView/pv/data/snapshot.h
+++ b/DSView/pv/data/snapshot.h
@@ -40,6 +40,7 @@ public:
     virtual void init() = 0;
 
 	uint64_t get_sample_count();
+    uint64_t get_ring_sample_count();
     uint64_t get_ring_start();
     uint64_t get_ring_end();
 
diff --git a/DSView/pv/sigsession.cpp b/DSView/pv/sigsession.cpp
index 2d398a74..444da686 100644
--- a/DSView/pv/sigsession.cpp
+++ b/DSView/pv/sigsession.cpp
@@ -85,6 +85,8 @@ namespace pv
         _data_lock = false;
         _data_updated = false;
         _opt_mode = OPT_SINGLE;
+        _rt_refresh_time_id = 0;
+        _rt_ck_refresh_time_id = 0;
 
         this->add_msg_listener(this);
 
@@ -113,6 +115,7 @@ namespace pv
         _feed_timer.SetCallback(std::bind(&SigSession::feed_timeout, this));
         _repeat_timer.SetCallback(std::bind(&SigSession::repeat_capture_wait_timeout, this));
         _repeat_wait_prog_timer.SetCallback(std::bind(&SigSession::repeat_wait_prog_timeout, this));
+        _refresh_rt_timer.SetCallback(std::bind(&SigSession::realtime_refresh_timeout, this));
     }
 
     SigSession::SigSession(SigSession &o)
@@ -374,6 +377,8 @@ namespace pv
         _trigger_flag = false;
         _trigger_ch = 0;
         _hw_replied = false;
+        _rt_refresh_time_id = 0;
+        _rt_ck_refresh_time_id = 0;
 
         int work_mode = _device_agent.get_work_mode();
         if (work_mode == DSO || work_mode == ANALOG)
@@ -472,6 +477,10 @@ namespace pv
             _capture_time_id++;
             _is_working = true;
             _callback->trigger_message(DSV_MSG_START_COLLECT_WORK);
+
+            if (is_realtime_mode()){
+                _refresh_rt_timer.Start(1000 / 30);
+            }
             return true;
         }
 
@@ -528,6 +537,7 @@ namespace pv
             _is_working = false;
             _repeat_timer.Stop();
             _repeat_wait_prog_timer.Stop();
+            _refresh_rt_timer.Stop();
             exit_capture();
             return;
         }
@@ -548,6 +558,7 @@ namespace pv
             _is_working = false;
             _repeat_timer.Stop();
             _repeat_wait_prog_timer.Stop();
+            _refresh_rt_timer.Stop();
 
             if (_repeat_hold_prg != 0 && is_repeat_mode()){
                 _repeat_hold_prg = 0;
@@ -635,7 +646,6 @@ namespace pv
 
         if (_data_updated)
         {
-            data_updated();
             _data_updated = false;
             _noData_cnt = 0;
             data_auto_unlock();
@@ -2001,4 +2011,20 @@ namespace pv
         return false;
     }
 
+    void SigSession::realtime_refresh_timeout()
+    {
+        _rt_refresh_time_id++;
+    }
+
+    bool SigSession::have_new_realtime_refresh(bool keep)
+    {
+        if (_rt_ck_refresh_time_id != _rt_refresh_time_id){
+            if (!keep){
+                _rt_ck_refresh_time_id = _rt_refresh_time_id;
+            }
+            return true;
+        }
+        return false;    
+    }
+
 } // namespace pv
diff --git a/DSView/pv/sigsession.h b/DSView/pv/sigsession.h
index 14435a88..ddce5473 100644
--- a/DSView/pv/sigsession.h
+++ b/DSView/pv/sigsession.h
@@ -367,6 +367,7 @@ public:
     void add_msg_listener(IMessageListener *ln);
     void broadcast_msg(int msg);
     bool switch_work_mode(int mode);
+    bool have_new_realtime_refresh(bool keep);
 
 private:
     void set_cur_samplelimits(uint64_t samplelimits);
@@ -441,6 +442,7 @@ private:
 
     void repeat_capture_wait_timeout();
     void repeat_wait_prog_timeout();
+    void realtime_refresh_timeout();
  
 private:
     mutable std::mutex      _sampling_mutex;
@@ -470,6 +472,7 @@ private:
     DsTimer     _out_timer;
     DsTimer     _repeat_timer;
     DsTimer     _repeat_wait_prog_timer;
+    DsTimer     _refresh_rt_timer;
     int         _noData_cnt;
     bool        _data_lock;
     bool        _data_updated;
@@ -499,6 +502,8 @@ private:
     int         _device_status;
     int         _capture_time_id;
     int         _confirm_store_time_id;
+    uint64_t    _rt_refresh_time_id;
+    uint64_t    _rt_ck_refresh_time_id;
     COLLECT_OPT_MODE    _opt_mode;
  
 
diff --git a/DSView/pv/toolbars/samplingbar.cpp b/DSView/pv/toolbars/samplingbar.cpp
index 50323550..d292ad9d 100644
--- a/DSView/pv/toolbars/samplingbar.cpp
+++ b/DSView/pv/toolbars/samplingbar.cpp
@@ -238,14 +238,15 @@ namespace pv
             {
                 QString iconPath = GetIconPath();
                 _configure_button.setIcon(QIcon(iconPath + "/params.svg"));
-                QString icon1 = _session->is_repeat_mode() ? "moder.svg" : "modes.svg";
-                _mode_button.setIcon(QIcon(iconPath + "/" + icon1));
+            
                 QString icon2 = _session->is_working() ? "stop.svg" : "start.svg";
                 _run_stop_button.setIcon(QIcon(iconPath + "/" + icon2));
                 _instant_button.setIcon(QIcon(iconPath + "/single.svg"));
                 _action_single->setIcon(QIcon(iconPath + "/oneloop.svg"));
                 _action_repeat->setIcon(QIcon(iconPath + "/repeat.svg"));
                 _action_realtime->setIcon(QIcon(iconPath + "/update.svg"));
+
+                update_mode_icon();
             }
         }
 
@@ -1031,8 +1032,7 @@ namespace pv
                 else
                 {
 
-                    QString icon = _session->is_repeat_mode() ? "/moder.svg" : "/modes.svg";
-                    _mode_button.setIcon(QIcon(iconPath + icon));
+                    update_mode_icon();
                     _mode_action->setVisible(true);
                 }
                 _run_stop_action->setVisible(true);
@@ -1062,13 +1062,11 @@ namespace pv
             QAction *act = qobject_cast<QAction *>(sender());
 
             if (act == _action_single)
-            {
-                _mode_button.setIcon(QIcon(iconPath + "/modes.svg"));
+            { 
                 _session->set_operation_mode(OPT_SINGLE);
             }
             else if (act == _action_repeat)
-            {
-                _mode_button.setIcon(QIcon(iconPath + "/moder.svg"));
+            { 
                 pv::dialogs::Interval interval_dlg(this);
 
                 interval_dlg.set_interval(_session->get_repeat_intvl());
@@ -1081,10 +1079,11 @@ namespace pv
                 }
             }
             else if (act == _action_realtime)
-            {
-                _mode_button.setIcon(QIcon(iconPath + "/update.svg"));
+            { 
                 _session->set_operation_mode(OPT_REALTIME);
             }
+
+            update_mode_icon();
         }
 
         void SamplingBar::update_device_list()
@@ -1181,14 +1180,14 @@ namespace pv
                 _instant_button.setIcon(!bEnable ? QIcon(iconPath + "/stop.svg") : QIcon(iconPath + "/single.svg"));
             else
                 _run_stop_button.setIcon(!bEnable ? QIcon(iconPath + "/stop.svg") : QIcon(iconPath + "/start.svg"));
-
-            _mode_button.setIcon(_session->is_repeat_mode() == false ? QIcon(iconPath + "/modes.svg") : QIcon(iconPath + "/moder.svg"));
-
+ 
             retranslateUi();
 
             if (bEnable){
                 _is_run_as_instant = false;
-            }            
+            }
+
+            update_mode_icon();       
          }
 
          ds_device_handle SamplingBar::get_next_device_handle()
@@ -1198,5 +1197,17 @@ namespace pv
              return h;
          }
 
+         void SamplingBar::update_mode_icon()
+         {  
+            QString iconPath = GetIconPath();
+
+            if (_session->is_repeat_mode())
+                _mode_button.setIcon(QIcon(iconPath + "/moder.svg"));
+            else if (_session->is_realtime_mode())
+                _mode_button.setIcon(QIcon(iconPath + "/update.svg"));
+            else
+                _mode_button.setIcon(QIcon(iconPath + "/modes.svg")); 
+         }
+
     } // namespace toolbars
 } // namespace pv
diff --git a/DSView/pv/toolbars/samplingbar.h b/DSView/pv/toolbars/samplingbar.h
index 4a724dec..c4a9c093 100644
--- a/DSView/pv/toolbars/samplingbar.h
+++ b/DSView/pv/toolbars/samplingbar.h
@@ -103,6 +103,7 @@ namespace pv
             void commit_settings();
             void setting_adj();
             void enable_toggle(bool enable);
+            void update_mode_icon();
 
         private slots:
             void on_mode();
diff --git a/DSView/pv/view/logicsignal.cpp b/DSView/pv/view/logicsignal.cpp
index 13a09486..0e8f2cd4 100644
--- a/DSView/pv/view/logicsignal.cpp
+++ b/DSView/pv/view/logicsignal.cpp
@@ -145,7 +145,7 @@ void LogicSignal::paint_mid(QPainter &p, int left, int right, QColor fore, QColo
     if (!snapshot->has_data(_probe->index))
         return;
 
-    const int64_t last_sample =  snapshot->get_sample_count() - 1;
+    const int64_t last_sample = snapshot->get_ring_sample_count() - 1;
 	const double samples_per_pixel = samplerate * scale;
 
     uint16_t width = right - left;
diff --git a/DSView/pv/view/view.cpp b/DSView/pv/view/view.cpp
index 92759344..38f509e0 100644
--- a/DSView/pv/view/view.cpp
+++ b/DSView/pv/view/view.cpp
@@ -1332,7 +1332,7 @@ void View::set_receive_len(uint64_t len)
     if (_time_viewport)
         _time_viewport->set_receive_len(len);
         
-    if (_fft_viewport)
+    if (_fft_viewport && _session->get_device()->get_work_mode() == DSO)
         _fft_viewport->set_receive_len(len);
 }
 
diff --git a/DSView/pv/view/viewport.cpp b/DSView/pv/view/viewport.cpp
index c2214705..c2f46d53 100644
--- a/DSView/pv/view/viewport.cpp
+++ b/DSView/pv/view/viewport.cpp
@@ -138,11 +138,19 @@ bool Viewport::event(QEvent *event)
 }
 
 void Viewport::paintEvent(QPaintEvent *event)
-{    
-    (void)event;
+{
+    (void)event; 
 
+    doPaint(true);
+}
+
+void Viewport::doPaint(bool bForce)
+{     
     using pv::view::Signal;
 
+   // if (_view.session().is_stopped_status())
+    //    dsv_info("paint"); 
+   
     QStyleOption o;
     o.initFrom(this);
     QPainter p(this);
@@ -153,7 +161,7 @@ void Viewport::paintEvent(QPaintEvent *event)
     QColor back(QWidget::palette().color(QWidget::backgroundRole()));
     fore.setAlpha(View::ForeAlpha);
     _view.set_back(false);
-
+  
     std::vector<Trace*> traces;
     _view.get_traces(_type, traces);
 
@@ -166,11 +174,15 @@ void Viewport::paintEvent(QPaintEvent *event)
     if (_view.session().get_device()->get_work_mode() == LOGIC ||
         _view.session().is_instant()) 
     {
-        if (_view.session().is_stopped_status() 
-            || _view.session().is_realtime_mode())
+        if (_view.session().is_stopped_status())
         {
             paintSignals(p, fore, back);
         }
+        else if (_view.session().is_realtime_mode())
+        {   
+            if (_view.session().have_new_realtime_refresh(false) || bForce)
+                paintSignals(p, fore, back);
+        }
         else if (_view.session().is_running_status()){
             if (_view.session().is_repeat_mode() && !_transfer_started) {
                 _view.set_capture_status();
@@ -735,20 +747,21 @@ void Viewport::mouseMoveEvent(QMouseEvent *event)
     _mouse_point = event->pos();
 
     measure();
+   
     update();
 }
 
 void Viewport::mouseReleaseEvent(QMouseEvent *event)
 {
-    assert(event);
+        assert(event);
 
-    bool quickScroll = AppConfig::Instance()._appOptions.quickScroll;
-    bool isMaxWindow = AppControl::Instance()->TopWindowIsMaximized();
+        bool quickScroll = AppConfig::Instance()._appOptions.quickScroll;
+        bool isMaxWindow = AppControl::Instance()->TopWindowIsMaximized();
     
-    if (_type != TIME_VIEW){
-        update();
-        return;
-    }
+        if (_type != TIME_VIEW){
+            update();
+            return;
+        }
   
         if ((_action_type == NO_ACTION) && (event->button() == Qt::LeftButton)) 
         {
@@ -1000,6 +1013,7 @@ void Viewport::mouseDoubleClickEvent(QMouseEvent *event)
             _view.add_cursor(view::Ruler::CursorColor[_view.get_cursorList().size() % 8], index);
             _view.show_cursors(true);
         }
+
         update();
     }
     else if (_view.session().get_device()->get_work_mode() == DSO
@@ -1189,6 +1203,12 @@ void Viewport::set_receive_len(quint64 length)
         else
             _sample_received += length;
     }
+
+    if (_view.session().is_realtime_mode() && _view.session().have_new_realtime_refresh(true) == false){
+        return;
+    }
+
+    // Received new data, and refresh the view.
     update();
 }
 
@@ -1714,7 +1734,7 @@ void Viewport::show_wait_trigger()
 }
 
 void Viewport::unshow_wait_trigger()
-{
+{   
     _waiting_trig = 0;
     update();
 }
diff --git a/DSView/pv/view/viewport.h b/DSView/pv/view/viewport.h
index 1825f42d..c5f290ac 100644
--- a/DSView/pv/view/viewport.h
+++ b/DSView/pv/view/viewport.h
@@ -100,12 +100,16 @@ public:
     void clear_dso_xm();
     void set_need_update(bool update);
     bool get_dso_trig_moved();
+    void set_receive_len(quint64 length);
+    void unshow_wait_trigger();
+    void show_wait_trigger();
 
 protected:
     bool event(QEvent *event) override;
     void paintEvent(QPaintEvent *event) override;
 
 private:
+    void doPaint(bool bForce);
     void mousePressEvent(QMouseEvent *event) override;
     void mouseMoveEvent(QMouseEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
@@ -129,11 +133,6 @@ private slots:
     void add_cursor_x();
     void add_cursor_y();
 
-public slots:
-    void show_wait_trigger();
-    void unshow_wait_trigger();
-    void set_receive_len(quint64 length);
-
 signals:
     void measure_updated();
     void prgRate(int progress);