diff --git a/plugins/samplemimo/testmi/testmigui.cpp b/plugins/samplemimo/testmi/testmigui.cpp
index 01c12b763..745369ee5 100644
--- a/plugins/samplemimo/testmi/testmigui.cpp
+++ b/plugins/samplemimo/testmi/testmigui.cpp
@@ -150,6 +150,15 @@ void TestMIGui::on_startStop_toggled(bool checked)
 
 void TestMIGui::on_streamIndex_currentIndexChanged(int index)
 {
+    if (ui->streamLock->isChecked())
+    {
+        m_spectrumStreamIndex = index;
+        m_deviceUISet->m_deviceAPI->setSpectrumSinkInput(true, m_spectrumStreamIndex);
+        ui->spectrumSource->blockSignals(true);
+        ui->spectrumSource->setCurrentIndex(index);
+        ui->spectrumSource->blockSignals(false);
+    }
+
     m_streamIndex = index;
     updateFileRecordStatus();
     updateSampleRateAndFrequency();
@@ -161,6 +170,23 @@ void TestMIGui::on_spectrumSource_currentIndexChanged(int index)
     m_spectrumStreamIndex = index;
     m_deviceUISet->m_deviceAPI->setSpectrumSinkInput(true, m_spectrumStreamIndex);
     updateSampleRateAndFrequency();
+
+    if (ui->streamLock->isChecked())
+    {
+        ui->streamIndex->blockSignals(true);
+        ui->streamIndex->setCurrentIndex(index);
+        ui->streamIndex->blockSignals(false);
+        m_streamIndex = index;
+        updateFileRecordStatus();
+        displaySettings();
+    }
+}
+
+void TestMIGui::on_streamLock_toggled(bool checked)
+{
+    if (checked && (ui->streamIndex->currentIndex() != ui->spectrumSource->currentIndex())) {
+        ui->spectrumSource->setCurrentIndex(ui->streamIndex->currentIndex());
+    }
 }
 
 void TestMIGui::on_centerFrequency_changed(quint64 value)
diff --git a/plugins/samplemimo/testmi/testmigui.h b/plugins/samplemimo/testmi/testmigui.h
index 0585f2674..eaff0fb03 100644
--- a/plugins/samplemimo/testmi/testmigui.h
+++ b/plugins/samplemimo/testmi/testmigui.h
@@ -85,6 +85,7 @@ private slots:
 	void on_startStop_toggled(bool checked);
     void on_streamIndex_currentIndexChanged(int index);
     void on_spectrumSource_currentIndexChanged(int index);
+    void on_streamLock_toggled(bool checked);
     void on_centerFrequency_changed(quint64 value);
     void on_autoCorr_currentIndexChanged(int index);
     void on_frequencyShift_changed(qint64 value);
diff --git a/plugins/samplemimo/testmi/testmigui.ui b/plugins/samplemimo/testmi/testmigui.ui
index ed074e225..e21fe1946 100644
--- a/plugins/samplemimo/testmi/testmigui.ui
+++ b/plugins/samplemimo/testmi/testmigui.ui
@@ -102,6 +102,24 @@
        </property>
       </widget>
      </item>
+     <item>
+      <widget class="QToolButton" name="streamLock">
+       <property name="toolTip">
+        <string>Lock spectrum display to stream selection</string>
+       </property>
+       <property name="text">
+        <string/>
+       </property>
+       <property name="icon">
+        <iconset resource="../../../sdrgui/resources/res.qrc">
+         <normaloff>:/unlocked.png</normaloff>
+         <normalon>:/locked.png</normalon>:/unlocked.png</iconset>
+       </property>
+       <property name="checkable">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
      <item>
       <spacer name="horizontalSpacer_7">
        <property name="orientation">