diff --git a/src/waveform/waveformwidgetfactory.cpp b/src/waveform/waveformwidgetfactory.cpp
index 5a8db447e626..e9ef018d043b 100644
--- a/src/waveform/waveformwidgetfactory.cpp
+++ b/src/waveform/waveformwidgetfactory.cpp
@@ -641,7 +641,7 @@ void WaveformWidgetFactory::setDefaultZoom(double zoom) {
         m_config->set(ConfigKey("[Waveform]","DefaultZoom"), ConfigValue(m_defaultZoom));
     }
 
-    for (const auto& holder : m_waveformWidgetHolders) {
+    for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
         holder.m_waveformViewer->setZoom(m_defaultZoom);
     }
 }
@@ -657,7 +657,7 @@ void WaveformWidgetFactory::setZoomSync(bool sync) {
     }
 
     double refZoom = m_waveformWidgetHolders[0].m_waveformWidget->getZoomFactor();
-    for (const auto& holder : m_waveformWidgetHolders) {
+    for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
         holder.m_waveformViewer->setZoom(refZoom);
     }
 }
@@ -668,7 +668,7 @@ void WaveformWidgetFactory::setDisplayBeatGridAlpha(int alpha) {
         return;
     }
 
-    for (const auto& holder : m_waveformWidgetHolders) {
+    for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
         holder.m_waveformWidget->setDisplayBeatGridAlpha(m_beatGridAlpha);
     }
 }
@@ -698,22 +698,22 @@ void WaveformWidgetFactory::setPlayMarkerPosition(double position) {
         m_config->setValue(ConfigKey("[Waveform]", "PlayMarkerPosition"), m_playMarkerPosition);
     }
 
-    for (const auto& holder : m_waveformWidgetHolders) {
+    for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
         holder.m_waveformWidget->setPlayMarkerPosition(m_playMarkerPosition);
     }
 }
 
 void WaveformWidgetFactory::notifyZoomChange(WWaveformViewer* viewer) {
     WaveformWidgetAbstract* pWaveformWidget = viewer->getWaveformWidget();
-    if (pWaveformWidget != nullptr && isZoomSync()) {
-        //qDebug() << "WaveformWidgetFactory::notifyZoomChange";
-        double refZoom = pWaveformWidget->getZoomFactor();
-
-        for (std::size_t i = 0; i < m_waveformWidgetHolders.size(); ++i) {
-            WaveformWidgetHolder& holder = m_waveformWidgetHolders[i];
-            if (holder.m_waveformViewer != viewer) {
-                holder.m_waveformViewer->setZoom(refZoom);
-            }
+    if (pWaveformWidget == nullptr || !isZoomSync()) {
+        return;
+    }
+    // qDebug() << "WaveformWidgetFactory::notifyZoomChange";
+    double refZoom = pWaveformWidget->getZoomFactor();
+
+    for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
+        if (holder.m_waveformViewer != viewer) {
+            holder.m_waveformViewer->setZoom(refZoom);
         }
     }
 }
@@ -802,7 +802,7 @@ void WaveformWidgetFactory::swap() {
         if (m_type) {   // no regular updates for an empty waveform
             // Show rendered buffer from last render() run
             //qDebug() << "swap() start" << m_vsyncThread->elapsed();
-            for (const auto& holder : m_waveformWidgetHolders) {
+            for (const auto& holder : std::as_const(m_waveformWidgetHolders)) {
                 WaveformWidgetAbstract* pWaveformWidget = holder.m_waveformWidget;
 
                 // Don't swap invalid / invisible widgets or widgets with an
@@ -1164,19 +1164,18 @@ WaveformWidgetType::Type WaveformWidgetFactory::findTypeFromHandleIndex(int inde
 }
 
 int WaveformWidgetFactory::findHandleIndexFromType(WaveformWidgetType::Type type) {
-    int index = -1;
-    for (int i = 0; i < m_waveformWidgetHandles.size(); i++) {
-        WaveformWidgetAbstractHandle& handle = m_waveformWidgetHandles[i];
+    int index = 0;
+    for (const auto& handle : std::as_const(m_waveformWidgetHandles)) {
         if (handle.m_type == type) {
-            index = i;
+            return index;
         }
+        index++;
     }
-    return index;
+    return -1;
 }
 
 QString WaveformWidgetFactory::getDisplayNameFromType(WaveformWidgetType::Type type) {
-    for (int i = 0; i < m_waveformWidgetHandles.size(); i++) {
-        WaveformWidgetAbstractHandle& handle = m_waveformWidgetHandles[i];
+    for (const auto& handle : std::as_const(m_waveformWidgetHandles)) {
         if (handle.m_type == type) {
             return handle.m_displayString;
         }