diff --git a/Code/Mantid/MantidPlot/src/AssociationsDialog.cpp b/Code/Mantid/MantidPlot/src/AssociationsDialog.cpp
index b3757eb9ae0b6bda3b42bfe2f34c98968b350a78..a0531f6bd72b32813b8b4a641f420d68b77121d6 100644
--- a/Code/Mantid/MantidPlot/src/AssociationsDialog.cpp
+++ b/Code/Mantid/MantidPlot/src/AssociationsDialog.cpp
@@ -48,8 +48,9 @@
 AssociationsDialog::AssociationsDialog( Graph* g, Qt::WFlags fl )
     : QDialog( g, fl )
 {
-    setName( "AssociationsDialog" );
-    setWindowTitle( tr( "MantidPlot - Plot Associations" ) );
+  setName( "AssociationsDialog" );
+  setWindowTitle( tr( "MantidPlot - Plot Associations" ) );
+  setModal(true);
   setSizeGripEnabled(true);
   setFocus();