Re #11406. Check for a null pointer.

Code/Mantid/MantidPlot/src/Mantid/MantidUI.cpp

@@ -2732,18 +2732,21 @@ void MantidUI::importNumSeriesLog(const QString &wsName, const QString &logName,
   if (filter && flt.filter())
   {
     QwtPlotCurve *c = g->curve(iFilterCurve);
-    // Set the right axis as Y axis for the filter curve.
-    c->setAxis(2,1);
-    // Set style #3 (HorizontalSteps) for curve 1
-    // Set scale of right Y-axis (#3) from 0 to 1
-    g->setCurveStyle(iFilterCurve,3);
-    g->setScale(3,0,1);
-    // Fill area under the curve with a pattern
-    QBrush br = QBrush(Qt::gray, Qt::Dense5Pattern);
-    g->setCurveBrush(iFilterCurve, br);
-    // Set line colour
-    QPen pn = QPen(Qt::gray);
-    g->setCurvePen(iFilterCurve, pn);
+    if ( c )
+    {
+      // Set the right axis as Y axis for the filter curve.
+      c->setAxis(2,1);
+      // Set style #3 (HorizontalSteps) for curve 1
+      // Set scale of right Y-axis (#3) from 0 to 1
+      g->setCurveStyle(iFilterCurve,3);
+      g->setScale(3,0,1);
+      // Fill area under the curve with a pattern
+      QBrush br = QBrush(Qt::gray, Qt::Dense5Pattern);
+      g->setCurveBrush(iFilterCurve, br);
+      // Set line colour
+      QPen pn = QPen(Qt::gray);
+      g->setCurvePen(iFilterCurve, pn);
+    }
   }
   g->setXAxisTitle(t->colLabel(0));
   g->setYAxisTitle(t->colLabel(1).section(".",0,0));