diff --git a/sdrgui/gui/glspectrumgui.cpp b/sdrgui/gui/glspectrumgui.cpp
index 1b01033ec..53fbae5df 100644
--- a/sdrgui/gui/glspectrumgui.cpp
+++ b/sdrgui/gui/glspectrumgui.cpp
@@ -24,6 +24,7 @@
 #include <QFileDialog>
 #include <QMessageBox>
 #include <QDesktopWidget>
+#include <QScreen>
 
 #include "gui/glspectrumgui.h"
 #include "dsp/fftwindow.h"
@@ -477,8 +478,8 @@ void GLSpectrumGUI::on_markers_clicked(bool checked)
     connect(m_markersDialog, SIGNAL(finished(int)), this, SLOT(closeMarkersDialog()));
 
     QPoint globalCursorPos = QCursor::pos();
-    int mouseScreen = qApp->desktop()->screenNumber(globalCursorPos);
-    QRect mouseScreenGeometry = qApp->desktop()->screen(mouseScreen)->geometry();
+    QScreen *screen = QGuiApplication::screenAt(globalCursorPos);
+    QRect mouseScreenGeometry = screen->geometry();
     QPoint localCursorPos = globalCursorPos - mouseScreenGeometry.topLeft();
     m_markersDialog->move(localCursorPos);
 
@@ -929,6 +930,20 @@ bool GLSpectrumGUI::handleMessage(const Message& message)
         ui->refLevel->blockSignals(false);
         return true;
     }
+    else if (GLSpectrumView::MsgReportHistogramMarkersChange::match(message))
+    {
+        if (m_markersDialog) {
+            m_markersDialog->updateHistogramMarkersDisplay();
+        }
+        return true;
+    }
+    else if (GLSpectrumView::MsgReportWaterfallMarkersChange::match(message))
+    {
+        if (m_markersDialog) {
+            m_markersDialog->updateWaterfallMarkersDisplay();
+        }
+        return true;
+    }
     else if (SpectrumVis::MsgStartStop::match(message))
     {
         const SpectrumVis::MsgStartStop& msg = (SpectrumVis::MsgStartStop&) message;
@@ -1035,6 +1050,8 @@ void GLSpectrumGUI::updateCalibrationPoints()
 
 void GLSpectrumGUI::on_measure_clicked(bool checked)
 {
+    (void) checked;
+
     SpectrumMeasurementsDialog measurementsDialog(
         m_glSpectrum,
         &m_settings,
diff --git a/sdrgui/gui/glspectrumview.cpp b/sdrgui/gui/glspectrumview.cpp
index b0946096b..ea37d0a9e 100644
--- a/sdrgui/gui/glspectrumview.cpp
+++ b/sdrgui/gui/glspectrumview.cpp
@@ -39,6 +39,8 @@ MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportWaterfallShare, Message)
 MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportFFTOverlap, Message)
 MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportPowerScale, Message)
 MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportCalibrationShift, Message)
+MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportHistogramMarkersChange, Message)
+MESSAGE_CLASS_DEFINITION(GLSpectrumView::MsgReportWaterfallMarkersChange, Message)
 
 const float GLSpectrumView::m_maxFrequencyZoom = 10.0f;
 const float GLSpectrumView::m_annotationMarkerHeight = 20.0f;
@@ -340,8 +342,12 @@ void GLSpectrumView::setDisplayWaterfall(bool display)
 {
     m_mutex.lock();
     m_displayWaterfall = display;
-    if (!display) {
+    if (!display)
+    {
         m_waterfallMarkers.clear();
+        if (m_messageQueueToGUI) {
+            m_messageQueueToGUI->push(new MsgReportWaterfallMarkersChange());
+        }
     }
     m_changesPending = true;
     stopDrag();
@@ -406,8 +412,12 @@ void GLSpectrumView::setDisplayMaxHold(bool display)
 {
     m_mutex.lock();
     m_displayMaxHold = display;
-    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram) {
+    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram)
+    {
         m_histogramMarkers.clear();
+        if (m_messageQueueToGUI) {
+            m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+        }
     }
     m_changesPending = true;
     stopDrag();
@@ -419,8 +429,12 @@ void GLSpectrumView::setDisplayCurrent(bool display)
 {
     m_mutex.lock();
     m_displayCurrent = display;
-    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram) {
+    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram)
+    {
         m_histogramMarkers.clear();
+        if (m_messageQueueToGUI) {
+            m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+        }
     }
     m_changesPending = true;
     stopDrag();
@@ -432,8 +446,12 @@ void GLSpectrumView::setDisplayHistogram(bool display)
 {
     m_mutex.lock();
     m_displayHistogram = display;
-    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram) {
+    if (!m_displayMaxHold && !m_displayCurrent && !m_displayHistogram)
+    {
         m_histogramMarkers.clear();
+        if (m_messageQueueToGUI) {
+            m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+        }
     }
     m_changesPending = true;
     stopDrag();
@@ -3663,6 +3681,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
             {
                 m_histogramMarkers.clear();
                 doUpdate = true;
+                if (m_messageQueueToGUI) {
+                    m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+                }
             }
         }
         else
@@ -3671,6 +3692,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
             {
                 m_histogramMarkers.pop_back();
                 doUpdate = true;
+                if (m_messageQueueToGUI) {
+                    m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+                }
             }
         }
 
@@ -3684,6 +3708,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
             {
                 m_waterfallMarkers.clear();
                 doUpdate = true;
+                if (m_messageQueueToGUI) {
+                    m_messageQueueToGUI->push(new MsgReportWaterfallMarkersChange());
+                }
             }
         }
         else
@@ -3692,6 +3719,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
             {
                 m_waterfallMarkers.pop_back();
                 doUpdate = true;
+                if (m_messageQueueToGUI) {
+                    m_messageQueueToGUI->push(new MsgReportWaterfallMarkersChange());
+                }
             }
         }
 
@@ -3748,6 +3778,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
                             m_linear ? 3 : 1);
                     }
 
+                    if (m_messageQueueToGUI) {
+                        m_messageQueueToGUI->push(new MsgReportHistogramMarkersChange());
+                    }
                     doUpdate = true;
                 }
             }
@@ -3792,6 +3825,9 @@ void GLSpectrumView::mousePressEvent(QMouseEvent* event)
                             true);
                     }
 
+                    if (m_messageQueueToGUI) {
+                        m_messageQueueToGUI->push(new MsgReportWaterfallMarkersChange());
+                    }
                     doUpdate = true;
                 }
             }
diff --git a/sdrgui/gui/glspectrumview.h b/sdrgui/gui/glspectrumview.h
index 25a5f598b..ddc7180e7 100644
--- a/sdrgui/gui/glspectrumview.h
+++ b/sdrgui/gui/glspectrumview.h
@@ -131,6 +131,24 @@ public:
         Real m_calibrationShiftdB;
     };
 
+    class MsgReportHistogramMarkersChange : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        MsgReportHistogramMarkersChange() :
+            Message()
+        {}
+    };
+
+    class MsgReportWaterfallMarkersChange : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        MsgReportWaterfallMarkersChange() :
+            Message()
+        {}
+    };
+
     GLSpectrumView(QWidget* parent = nullptr);
     virtual ~GLSpectrumView();
 
diff --git a/sdrgui/gui/spectrummarkersdialog.cpp b/sdrgui/gui/spectrummarkersdialog.cpp
index 935621c79..28f6b9e7e 100644
--- a/sdrgui/gui/spectrummarkersdialog.cpp
+++ b/sdrgui/gui/spectrummarkersdialog.cpp
@@ -825,3 +825,17 @@ void SpectrumMarkersDialog::on_showSelect_currentIndexChanged(int index)
     m_markersDisplay = (SpectrumSettings::MarkersDisplay) index;
     emit updateMarkersDisplay();
 }
+
+void SpectrumMarkersDialog::updateHistogramMarkersDisplay()
+{
+    m_histogramMarkerIndex = std::max(m_histogramMarkerIndex, m_histogramMarkers.size() - 1);
+    ui->marker->setMaximum(m_histogramMarkers.size() - 1);
+    displayHistogramMarker();
+}
+
+void SpectrumMarkersDialog::updateWaterfallMarkersDisplay()
+{
+    m_waterfallMarkerIndex = std::max(m_waterfallMarkerIndex, m_waterfallMarkers.size() - 1);
+    ui->wMarker->setMaximum(m_waterfallMarkers.size() - 1);
+    displayWaterfallMarker();
+}
diff --git a/sdrgui/gui/spectrummarkersdialog.h b/sdrgui/gui/spectrummarkersdialog.h
index bfdb53da6..95e5d11ee 100644
--- a/sdrgui/gui/spectrummarkersdialog.h
+++ b/sdrgui/gui/spectrummarkersdialog.h
@@ -46,6 +46,8 @@ public:
     void setCenterFrequency(qint64 centerFrequency) { m_centerFrequency = centerFrequency; }
     void setPower(float power) { m_power = power; }
     void setTime(float time) { m_time = time; }
+    void updateHistogramMarkersDisplay(); //!< called from spectrum view
+    void updateWaterfallMarkersDisplay(); //!< called from spectrum view
 
 private:
     Ui::SpectrumMarkersDialog* ui;