diff --git a/src/plotcontrolpanel.cpp b/src/plotcontrolpanel.cpp
--- a/src/plotcontrolpanel.cpp
+++ b/src/plotcontrolpanel.cpp
@@ -386,6 +386,7 @@ void PlotControlPanel::saveSettings(QSet
 {
     settings->beginGroup(SettingGroup_Plot);
     settings->setValue(SG_Plot_NumOfSamples, numOfSamples());
+    settings->setValue(SG_Plot_PlotWidth, ui->spPlotWidth->value());
     settings->setValue(SG_Plot_IndexAsX, xAxisAsIndex());
     settings->setValue(SG_Plot_XMax, xMax());
     settings->setValue(SG_Plot_XMin, xMin());
@@ -400,6 +401,8 @@ void PlotControlPanel::loadSettings(QSet
     settings->beginGroup(SettingGroup_Plot);
     ui->spNumOfSamples->setValue(
         settings->value(SG_Plot_NumOfSamples, numOfSamples()).toInt());
+    ui->spPlotWidth->setValue(
+        settings->value(SG_Plot_PlotWidth, ui->spPlotWidth->value()).toInt());
     ui->cbIndex->setChecked(
         settings->value(SG_Plot_IndexAsX, xAxisAsIndex()).toBool());
     ui->spXmax->setValue(settings->value(SG_Plot_XMax, xMax()).toDouble());
diff --git a/src/plotcontrolpanel.h b/src/plotcontrolpanel.h
--- a/src/plotcontrolpanel.h
+++ b/src/plotcontrolpanel.h
@@ -46,6 +46,7 @@ public:
     bool   xAxisAsIndex() const;
     double xMax() const;
     double xMin() const;
+    /// Returns the plot width adjusted for x axis scaling.
     double plotWidth() const;
 
     void setChannelInfoModel(ChannelInfoModel* model);
diff --git a/src/setting_defines.h b/src/setting_defines.h
--- a/src/setting_defines.h
+++ b/src/setting_defines.h
@@ -76,6 +76,7 @@ const char SG_Channels_Visible[] = "visi
 
 // plot settings keys
 const char SG_Plot_NumOfSamples[] = "numOfSamples";
+const char SG_Plot_PlotWidth[] = "plotWidth";
 const char SG_Plot_IndexAsX[] = "indexAsX";
 const char SG_Plot_XMax[] = "xMax";
 const char SG_Plot_XMin[] = "xMin";