diff --git a/src/CpintPlot.cpp b/src/CpintPlot.cpp
index 7009eeb47..4f3d33340 100644
--- a/src/CpintPlot.cpp
+++ b/src/CpintPlot.cpp
@@ -37,12 +37,12 @@
 
 #define USE_T0_IN_CP_MODEL 0 // added djconnel 08Apr2009: allow 3-parameter CP model
 
-CpintPlot::CpintPlot(QString p) :
+CpintPlot::CpintPlot(QString p, const Zones *zones) :
     needToScanRides(true),
     path(p),
     thisCurve(NULL),
     CPCurve(NULL),
-    zones(NULL),
+    zones(zones),
     energyMode_(false)
 {
     assert(!USE_T0_IN_CP_MODEL); // doesn't work with energyMode=true
@@ -585,7 +585,6 @@ CpintPlot::calculate(RideItem *rideItem)
     QDateTime dateTime = rideItem->dateTime;
     QDir dir(path);
     QFileInfo file(fileName);
-    zones = rideItem->zones;
 
     if (needToScanRides) {
         bests.clear();
diff --git a/src/CpintPlot.h b/src/CpintPlot.h
index 9dd381c7e..391b714be 100644
--- a/src/CpintPlot.h
+++ b/src/CpintPlot.h
@@ -36,7 +36,7 @@ class CpintPlot : public QwtPlot
 
     public:
 
-        CpintPlot(QString path);
+        CpintPlot(QString path, const Zones *zones);
         bool needToScanRides;
 
         const QwtPlotCurve *getThisCurve() const { return thisCurve; }
@@ -72,7 +72,7 @@ class CpintPlot : public QwtPlot
         QVector<QDate> bestDates;
         QDate startDate;
         QDate endDate;
-        Zones *zones;
+        const Zones *zones;
         // keys are CPI files contributing to bests (at least originally)
         QHash<QString,bool> cpiDataInBests;
         bool energyMode_;
diff --git a/src/CriticalPowerWindow.cpp b/src/CriticalPowerWindow.cpp
index e628f5522..e7a80dd11 100644
--- a/src/CriticalPowerWindow.cpp
+++ b/src/CriticalPowerWindow.cpp
@@ -34,7 +34,7 @@ CriticalPowerWindow::CriticalPowerWindow(const QDir &home, MainWindow *parent) :
 {
     QVBoxLayout *vlayout = new QVBoxLayout;
 
-    cpintPlot = new CpintPlot(home.path());
+    cpintPlot = new CpintPlot(home.path(), mainWindow->zones);
     vlayout->addWidget(cpintPlot);
 
     QFormLayout *cpintPickerLayout = new QFormLayout;