diff --git a/lib/jkqtcommon/jkqtpdrawingtools.cpp b/lib/jkqtcommon/jkqtpdrawingtools.cpp
index a0fc2a680a..69115205cd 100644
--- a/lib/jkqtcommon/jkqtpdrawingtools.cpp
+++ b/lib/jkqtcommon/jkqtpdrawingtools.cpp
@@ -446,7 +446,7 @@ QList<QPolygonF > JKQTPClipPolyLines(const QList<QPolygonF > &polylines_in, cons
                 } else if (l==lclipped) {
                     if (out.last().size()==0) {
                         out.last()<<lclipped.p1();
-                    } if (out.last().last()!=lclipped.p1()) {
+                    } else if (out.last().last()!=lclipped.p1()) {
                         out<<QPolygonF();
                         out.last()<<lclipped.p1();
                     }
@@ -454,7 +454,7 @@ QList<QPolygonF > JKQTPClipPolyLines(const QList<QPolygonF > &polylines_in, cons
                 } else if (l.p1()==lclipped.p1() && l.p2()!=lclipped.p2()) {
                     if (out.last().size()==0) {
                         out.last()<<lclipped.p1();
-                    } if (out.last().last()!=lclipped.p1()) {
+                    } else if (out.last().last()!=lclipped.p1()) {
                         out<<QPolygonF();
                         out.last()<<lclipped.p1();
                     }
@@ -463,7 +463,7 @@ QList<QPolygonF > JKQTPClipPolyLines(const QList<QPolygonF > &polylines_in, cons
                 } else if (l.p1()!=lclipped.p1() && l.p2()==lclipped.p2()) {
                     if (out.last().size()==0) {
                         out.last()<<lclipped.p1();
-                    } if (out.last().last()!=lclipped.p1()) {
+                    } else if (out.last().last()!=lclipped.p1()) {
                         out<<QPolygonF();
                         out.last()<<lclipped.p1();
                     }
@@ -481,3 +481,12 @@ QList<QPolygonF > JKQTPClipPolyLines(const QList<QPolygonF > &polylines_in, cons
     }
     return out;
 }
+
+QList<QPolygonF> JKQTPSimplifyPolyLines(const QList<QPolygonF> &lines_in, double maxDeltaXY)
+{
+    QList<QPolygonF> l;
+    for (const QPolygonF& p: lines_in) {
+        l<<JKQTPSimplifyPolyLines(p, maxDeltaXY);
+    }
+    return l;
+}
diff --git a/lib/jkqtcommon/jkqtpdrawingtools.h b/lib/jkqtcommon/jkqtpdrawingtools.h
index fd7ab0e67c..fd2fb1f49c 100644
--- a/lib/jkqtcommon/jkqtpdrawingtools.h
+++ b/lib/jkqtcommon/jkqtpdrawingtools.h
@@ -400,6 +400,15 @@ JKQTCOMMON_LIB_EXPORT QList<QPolygonF> JKQTPClipPolyLines(const QList<QPolygonF>
 */
 JKQTCOMMON_LIB_EXPORT QList<QPolygonF> JKQTPClipPolyLine(const QPolygonF & polyline_in, const QRectF& clipRect);
 
+/*! \brief tries to reduce the complexity of the given list of poly-lines \a lines_in, but keeping the appearance as if all lines were drawn
+    \ingroup jkqtptools_drawing
+
+    \param lines_in list of poly-lines to be simplified
+    \param maxDeltaXY a group has to be either less wide or less high than this, typically equals the linewidth of the poly-line
+    \return a simplified version of lines_in
+*/
+JKQTCOMMON_LIB_EXPORT QList<QPolygonF> JKQTPSimplifyPolyLines(const QList<QPolygonF>& lines_in, double maxDeltaXY=1.0);
+
 /*! \brief tries to reduce the complexity of the given poly-line \a lines_in, but keeping the appearance as if all lines were drawn
     \ingroup jkqtptools_drawing
 
diff --git a/lib/jkqtplotter/graphs/jkqtpscatter.cpp b/lib/jkqtplotter/graphs/jkqtpscatter.cpp
index 4f807fecb0..d5733aacf5 100644
--- a/lib/jkqtplotter/graphs/jkqtpscatter.cpp
+++ b/lib/jkqtplotter/graphs/jkqtpscatter.cpp
@@ -124,11 +124,12 @@ void JKQTPXYLineGraph::draw(JKQTPEnhancedPainter& painter) {
             if (drawLine) {
                 //qDebug()<<"JKQTPXYLineGraph::draw(): vec_linesP.size()=="<<vec_linesP.size();
 
-                const QList<QPolygonF> linesToDraw=JKQTPClipPolyLines(vec_linesP, cliprect);
+                QList<QPolygonF> linesToDraw;
+                if (getUseNonvisibleLineCompression()) linesToDraw=JKQTPClipPolyLines(JKQTPSimplifyPolyLines(vec_linesP, p.widthF()*getNonvisibleLineCompressionAgressiveness()), cliprect);
+                else linesToDraw=JKQTPClipPolyLines(vec_linesP, cliprect);
                 //qDebug()<<"JKQTPXYLineGraph::draw(): linesToDraw.size()=="<<linesToDraw.size()<<", clip: x="<<xmin<<".."<<xmax<<", y="<<ymin<<".."<<ymax;
-                for (const auto &linesPFromV : linesToDraw) {
+                for (const auto &linesP : linesToDraw) {
                     //qDebug()<<"JKQTPXYLineGraph::draw():   linesPFromV.size()=="<<linesPFromV.size()<<"   useNonvisibleLineCompression="<<getUseNonvisibleLineCompression();
-                    const QPolygonF linesP=getUseNonvisibleLineCompression()?QPolygonF(JKQTPSimplifyPolyLines(linesPFromV, p.widthF()*getNonvisibleLineCompressionAgressiveness())):QPolygonF(linesPFromV);
                     //qDebug()<<"JKQTPXYLineGraph::draw():     --> linesP.size()=="<<linesP.size();
                     if (linesP.size()>0) {
                         if (isHighlighted()) {