diff --git a/doc/dox/whatsnew.dox b/doc/dox/whatsnew.dox
index 017226cc22..a26ec32eb7 100644
--- a/doc/dox/whatsnew.dox
+++ b/doc/dox/whatsnew.dox
@@ -28,6 +28,7 @@ Changes, compared to  \ref page_whatsnew_V2019_11 "v2019.11" include:
   <li>improved/breaking change: reworked class hierarchy of parsed function plots and declared several setters as slots.</li>
   <li>improved/breaking change: reworked class hierarchy of bar & impulse charts.</li>
   <li>improved/breaking change: reworked class hierarchy of range charts.</li>
+  <li>improved/breaking change: reworked class hierarchy of special line (step) graphs.</li>
   <li>improved/breaking change: reworked graph Base-Classes (promoted several setters to slots, added Q_PROPERTY- and Q_ENUM-declarations...)</li>
   <li>improved/breaking change: made more functions and function parameters const</li>
   <li>bugfixed/improved: aspect ratio handling in JKQTPlotter.</li>
diff --git a/lib/jkqtplotter/graphs/jkqtpspecialline.cpp b/lib/jkqtplotter/graphs/jkqtpspecialline.cpp
index 35a621d1a2..c02a0b592c 100644
--- a/lib/jkqtplotter/graphs/jkqtpspecialline.cpp
+++ b/lib/jkqtplotter/graphs/jkqtpspecialline.cpp
@@ -34,14 +34,9 @@
 
 
 
-
-
-JKQTPSpecialLineHorizontalGraph::JKQTPSpecialLineHorizontalGraph(JKQTBasePlotter* parent):
-    JKQTPXYBaselineGraph(parent)
+JKQTPSpecialLineGraphBase::JKQTPSpecialLineGraphBase(JKQTBasePlotter* parent):
+    JKQTPXYBaselineGraph(parent), m_drawSymbols(false), m_specialLineType(JKQTPStepLeft)
 {
-    m_drawSymbols=false;
-    m_specialLineType=JKQTPStepLeft;
-
     parentPlotStyle=-1;
     initLineStyle(parent, parentPlotStyle);
     initFillStyle(parent, parentPlotStyle);
@@ -49,14 +44,7 @@ JKQTPSpecialLineHorizontalGraph::JKQTPSpecialLineHorizontalGraph(JKQTBasePlotter
     setFillCurve(false);
 }
 
-
-JKQTPSpecialLineHorizontalGraph::JKQTPSpecialLineHorizontalGraph(JKQTPlotter* parent):
-    JKQTPSpecialLineHorizontalGraph(parent->getPlotter())
-{
-}
-
-
-void JKQTPSpecialLineHorizontalGraph::drawKeyMarker(JKQTPEnhancedPainter& painter, QRectF& rect) {
+void JKQTPSpecialLineGraphBase::drawKeyMarker(JKQTPEnhancedPainter& painter, QRectF& rect) {
     painter.save(); auto __finalpaint=JKQTPFinally([&painter]() {painter.restore();});
     QPen p=getLinePen(painter, parent);
     QPen np(Qt::NoPen);
@@ -73,33 +61,34 @@ void JKQTPSpecialLineHorizontalGraph::drawKeyMarker(JKQTPEnhancedPainter& painte
 
 }
 
-QColor JKQTPSpecialLineHorizontalGraph::getKeyLabelColor() const {
+
+QColor JKQTPSpecialLineGraphBase::getKeyLabelColor() const {
     return getLineColor();
 }
 
-void JKQTPSpecialLineHorizontalGraph::setDrawSymbols(bool __value)
+void JKQTPSpecialLineGraphBase::setDrawSymbols(bool __value)
 {
     m_drawSymbols=__value;
 }
 
-bool JKQTPSpecialLineHorizontalGraph::getDrawSymbols() const
+bool JKQTPSpecialLineGraphBase::getDrawSymbols() const
 {
     return m_drawSymbols;
 }
 
 
-void JKQTPSpecialLineHorizontalGraph::setSpecialLineType(const JKQTPSpecialLineType &__value)
+void JKQTPSpecialLineGraphBase::setSpecialLineType(const JKQTPSpecialLineType &__value)
 {
     this->m_specialLineType = __value;
 }
 
-JKQTPSpecialLineType JKQTPSpecialLineHorizontalGraph::getSpecialLineType() const
+JKQTPSpecialLineType JKQTPSpecialLineGraphBase::getSpecialLineType() const
 {
     return this->m_specialLineType;
 }
 
 
-void JKQTPSpecialLineHorizontalGraph::setColor(QColor c)
+void JKQTPSpecialLineGraphBase::setColor(QColor c)
 {
     setLineColor(c);
     setSymbolColor(c);
@@ -110,6 +99,21 @@ void JKQTPSpecialLineHorizontalGraph::setColor(QColor c)
 }
 
 
+
+JKQTPSpecialLineHorizontalGraph::JKQTPSpecialLineHorizontalGraph(JKQTBasePlotter* parent):
+    JKQTPSpecialLineGraphBase(parent)
+{
+}
+
+
+JKQTPSpecialLineHorizontalGraph::JKQTPSpecialLineHorizontalGraph(JKQTPlotter* parent):
+    JKQTPSpecialLineHorizontalGraph(parent->getPlotter())
+{
+}
+
+
+
+
 void JKQTPSpecialLineHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
 #ifdef JKQTBP_AUTOTIMER
     JKQTPAutoOutputTimer jkaaot("JKQTPSpecialLineHorizontalGraph::draw");
@@ -136,10 +140,6 @@ void JKQTPSpecialLineHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
 
         double xold=-1;
         double yold=-1;
-    //    double xstart=-1;
-    //    double ystart=-1;
-        //double x0=transformX(0);
-        //if (parent->getXAxis()->isLogAxis()) x0=transformX(parent->getXAxis()->getMin());
         double y0=transformY(getBaseline());
         if (parent->getYAxis()->isLogAxis()) {
             y0=transformY(parent->getYAxis()->getMin());
@@ -293,12 +293,12 @@ void JKQTPSpecialLineHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
 
 
 JKQTPSpecialLineVerticalGraph::JKQTPSpecialLineVerticalGraph(JKQTBasePlotter *parent):
-    JKQTPSpecialLineHorizontalGraph(parent)
+    JKQTPSpecialLineGraphBase(parent)
 {
 }
 
 JKQTPSpecialLineVerticalGraph::JKQTPSpecialLineVerticalGraph(JKQTPlotter *parent):
-    JKQTPSpecialLineHorizontalGraph(parent)
+    JKQTPSpecialLineVerticalGraph(parent->getPlotter())
 {
 
 }
diff --git a/lib/jkqtplotter/graphs/jkqtpspecialline.h b/lib/jkqtplotter/graphs/jkqtpspecialline.h
index d255d287be..0d1c43e2e5 100644
--- a/lib/jkqtplotter/graphs/jkqtpspecialline.h
+++ b/lib/jkqtplotter/graphs/jkqtpspecialline.h
@@ -43,60 +43,82 @@ class JKQTPDatastore;
 
 
 
-/*! \brief This implements a step plot with values \f$ \left(x, f(x) \right) \f$
-    \ingroup jkqtplotter_linesymbolgraphs_simple
-
-    \image html stepplots.png
-
-    \see JKQTPSpecialLineVerticalGraph, JKQTPFilledCurveXGraph, \ref JKQTPlotterSpecialStepLinePlot
+/** \brief a Base class for special line graphs (steps ...) like e.g. JKQTPSpecialLineHorizontalGraph
+ *  \ingroup jkqtplotter_linesymbolgraphs_simple
+ *
+ *  \image html stepplots.png
+ *
+ *  \see JKQTPSpecialLineHorizontalGraph, JKQTPSpecialLineVerticalGraph
  */
-class JKQTPLOTTER_LIB_EXPORT JKQTPSpecialLineHorizontalGraph: public JKQTPXYBaselineGraph, public JKQTPGraphLineAndFillStyleMixin, public JKQTPGraphSymbolStyleMixin {
-        Q_OBJECT
-    public:
-        /** \brief class constructor */
-        JKQTPSpecialLineHorizontalGraph(JKQTBasePlotter* parent=nullptr);
-        /** \brief class constructor */
-        JKQTPSpecialLineHorizontalGraph(JKQTPlotter* parent);
+class JKQTPLOTTER_LIB_EXPORT JKQTPSpecialLineGraphBase: public JKQTPXYBaselineGraph, public JKQTPGraphLineAndFillStyleMixin, public JKQTPGraphSymbolStyleMixin {
+    Q_OBJECT
+public:
+    /** \brief class constructor */
+    explicit JKQTPSpecialLineGraphBase(JKQTBasePlotter* parent=nullptr);
 
-        /** \brief plots the graph to the plotter object specified as parent */
-        virtual void draw(JKQTPEnhancedPainter& painter) override;
-        /** \brief plots a key marker inside the specified rectangle \a rect */
-        virtual void drawKeyMarker(JKQTPEnhancedPainter& painter, QRectF& rect) override;
-        /** \brief returns the color to be used for the key label */
-        virtual QColor getKeyLabelColor() const override;
+    /** \brief returns the color to be used for the key label */
+    virtual QColor getKeyLabelColor() const override;
+    /** \brief plots a key marker inside the specified rectangle \a rect */
+    virtual void drawKeyMarker(JKQTPEnhancedPainter& painter, QRectF& rect) override;
 
 
-        /*! sets whether to draw symbols */
-        void setDrawSymbols(bool __value);
-        /*! returns whether symbols are drawn */
-        bool getDrawSymbols() const;
-        /** \brief set the type of connecting (step-)lines */
-        void setSpecialLineType(const JKQTPSpecialLineType & __value);
-        /** \brief get the type of connecting (step-)lines */
-        JKQTPSpecialLineType getSpecialLineType() const;
+    /** \copydoc m_drawSymbols */
+    bool getDrawSymbols() const;
+    /** \copydoc m_specialLineType */
+    JKQTPSpecialLineType getSpecialLineType() const;
 
-        /** \brief set line-color, fill color and symbol color */
-        void setColor(QColor c);
-    protected:
+    Q_PROPERTY(bool drawSymbols READ getDrawSymbols WRITE setDrawSymbols)
+    Q_PROPERTY(JKQTPSpecialLineType specialLineType READ getSpecialLineType WRITE setSpecialLineType)
+public slots:
+    /** \brief set line-color, fill color and symbol color */
+    void setColor(QColor c);
+    /** \copydoc m_drawSymbols */
+    void setDrawSymbols(bool __value);
+    /** \copydoc m_specialLineType */
+    void setSpecialLineType(const JKQTPSpecialLineType & __value);
+protected:
 
-        /** \brief indicates whether to draw a symbols or not */
-        bool m_drawSymbols;
-        /** \brief type of connecting (step)lines */
-        JKQTPSpecialLineType m_specialLineType;
+    /** \brief indicates whether to draw a symbols at the datapoints, or not */
+    bool m_drawSymbols;
+    /** \brief type of connecting (step)lines */
+    JKQTPSpecialLineType m_specialLineType;
 
 
 };
 
 
+/** \brief This implements a step plot with values \f$ \left(x, f(x) \right) \f$
+ *  \ingroup jkqtplotter_linesymbolgraphs_simple
+ *
+ *  \image html stepplots.png
+ *
+ *  \see JKQTPSpecialLineVerticalGraph, \ref JKQTPlotterSpecialStepLinePlot
+ */
+class JKQTPLOTTER_LIB_EXPORT JKQTPSpecialLineHorizontalGraph: public JKQTPSpecialLineGraphBase {
+    Q_OBJECT
+public:
+    /** \brief class constructor */
+    JKQTPSpecialLineHorizontalGraph(JKQTBasePlotter* parent=nullptr);
+    /** \brief class constructor */
+    JKQTPSpecialLineHorizontalGraph(JKQTPlotter* parent);
+
+    /** \brief plots the graph to the plotter object specified as parent */
+    virtual void draw(JKQTPEnhancedPainter& painter) override;
+
+protected:
+
+};
+
+
 
 /*! \brief This implements a step plot with values \f$ \left(f(y), y \right) \f$
     \ingroup jkqtplotter_linesymbolgraphs_simple
 
     \image html stepplots_vertical.png
 
-    \see JKQTPSpecialLineHorizontalGraph, JKQTPFilledCurveYGraph, \ref JKQTPlotterSpecialStepLinePlot
+    \see JKQTPSpecialLineHorizontalGraph, \ref JKQTPlotterSpecialStepLinePlot
  */
-class JKQTPLOTTER_LIB_EXPORT JKQTPSpecialLineVerticalGraph: public JKQTPSpecialLineHorizontalGraph {
+class JKQTPLOTTER_LIB_EXPORT JKQTPSpecialLineVerticalGraph: public JKQTPSpecialLineGraphBase {
         Q_OBJECT
     public:
         /** \brief class constructor */