diff --git a/Code/Mantid/MantidPlot/src/Mantid/MantidUI.cpp b/Code/Mantid/MantidPlot/src/Mantid/MantidUI.cpp
index b287de7390b7e2674564ff189d3f96f9542d53e8..ff727f11f850177439bc7870e69f3df5248cd797 100644
--- a/Code/Mantid/MantidPlot/src/Mantid/MantidUI.cpp
+++ b/Code/Mantid/MantidPlot/src/Mantid/MantidUI.cpp
@@ -3129,7 +3129,7 @@ MultiLayer* MantidUI::plot1D(const QMultiMap<QString,int>& toPlot, bool spectrum
     if (ask.clickedButton() != confirmButton) return NULL;
   }
   // Force waterfall option to false if only 1 curve
-  if(toPlot.size() == 1) waterfallPlot = false;
+  if((NULL==plotWindow || clearWindow == true) && toPlot.size() == 1) waterfallPlot = false;
 
   QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));