diff --git a/examples/second_axis/README.md b/examples/second_axis/README.md
index 866303c8b8..d8b928236d 100644
--- a/examples/second_axis/README.md
+++ b/examples/second_axis/README.md
@@ -131,5 +131,6 @@ If we set seondary axes for the x-axis instead of the y-axis, i.e. use
     // ...
 ```
 we get a plot like this:
+
 ![second_axis_hor](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/second_axis_hor.png)
 
diff --git a/lib/jkqtplotter/jkqtpbaseplotter.cpp b/lib/jkqtplotter/jkqtpbaseplotter.cpp
index 80503f4f42..c756abf540 100644
--- a/lib/jkqtplotter/jkqtpbaseplotter.cpp
+++ b/lib/jkqtplotter/jkqtpbaseplotter.cpp
@@ -3337,14 +3337,20 @@ bool JKQTBasePlotter::hasYAxis(JKQTPCoordinateAxisRef axis) const
 
 QSet<JKQTPCoordinateAxisRef> JKQTBasePlotter::getAvailableXAxisRefs(bool includePrimary) const
 {
-    QSet<JKQTPCoordinateAxisRef> res(secondaryXAxis.keyBegin(),secondaryXAxis.keyEnd());
+    QSet<JKQTPCoordinateAxisRef> res;
+    for (auto it=secondaryXAxis.begin(); it!=secondaryXAxis.end(); ++it) {
+        res.insert(it.key());
+    }
     if (includePrimary) res.insert(JKQTPPrimaryAxis);
         return res;
 }
 
 QSet<JKQTPCoordinateAxisRef> JKQTBasePlotter::getAvailableYAxisRefs(bool includePrimary) const
 {
-    QSet<JKQTPCoordinateAxisRef> res(secondaryYAxis.keyBegin(),secondaryYAxis.keyEnd());
+    QSet<JKQTPCoordinateAxisRef> res;
+    for (auto it=secondaryYAxis.begin(); it!=secondaryYAxis.end(); ++it) {
+        res.insert(it.key());
+    }
     if (includePrimary) res.insert(JKQTPPrimaryAxis);
     return res;
 }