diff --git a/src/mainwindow.h b/src/mainwindow.h
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -44,6 +44,7 @@
 #include "channelmanager.h"
 #include "snapshotmanager.h"
 #include "plotmanager.h"
+#include "plotmenu.h"
 #include "datarecorder.h"
 #include "updatecheckdialog.h"
 
@@ -78,6 +79,7 @@ private:
     QList<QwtPlotCurve*> curves;
     ChannelManager channelMan;
     PlotManager* plotMan;
+    QWidget* secondaryPlot;
     SnapshotManager snapshotMan;
     DataRecorder recorder;       // operated by `recordPanel`
 
@@ -86,9 +88,16 @@ private:
     DataFormatPanel dataFormatPanel;
     RecordPanel recordPanel;
     PlotControlPanel plotControlPanel;
+    PlotMenu plotMenu;
     UpdateCheckDialog updateCheckDialog;
 
+    /// Returns true if demo is running
     bool isDemoRunning();
+    /// Display a secondary plot in the splitter, removing and
+    /// deleting previous one if it exists
+    void showSecondary(QWidget* wid);
+    /// Hide secondary plot
+    void hideSecondary();
     /// Stores settings for all modules
     void saveAllSettings(QSettings* settings);
     /// Load settings for all modules
@@ -111,6 +120,8 @@ private slots:
     void clearPlot();
     void onSpsChanged(unsigned sps);
     void enableDemo(bool enabled);
+    void showBarPlot(bool show);
+
     void onExportCsv();
     void onSaveSettings();
     void onLoadSettings();