diff --git a/app/rtplot/src/main/java/org/csstudio/javafx/rtplot/internal/TracePainter.java b/app/rtplot/src/main/java/org/csstudio/javafx/rtplot/internal/TracePainter.java
index ddba1f3fa4..7ff1ca6d0f 100644
--- a/app/rtplot/src/main/java/org/csstudio/javafx/rtplot/internal/TracePainter.java
+++ b/app/rtplot/src/main/java/org/csstudio/javafx/rtplot/internal/TracePainter.java
@@ -297,7 +297,7 @@ final private void drawValueStaircase(final Graphics2D gc,
             final PlotDataItem<XTYPE> item = data.get(i);
             final int x = clipX(Math.round(x_transform.transform(item.getPosition())));
             final double value = item.getValue();
-            if (poly_x.size() > 0  && x != last_x && !Double.isNaN(value))
+            if (poly_x.size() > 0  && x != last_x)
             {   // Staircase from last 'y'..
                 poly_x.add(x);
                 poly_y.add(last_y);