diff --git a/prism/src/chart/MultiGraphOptions.java b/prism/src/chart/MultiGraphOptions.java
index 0e646722..ab0e0781 100644
--- a/prism/src/chart/MultiGraphOptions.java
+++ b/prism/src/chart/MultiGraphOptions.java
@@ -83,7 +83,7 @@ public class MultiGraphOptions extends JDialog
 		pack();
 		setLocationRelativeTo(getParent()); // centre
 		//show();
-		setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
+		setDefaultCloseOperation(javax.swing.JFrame.DISPOSE_ON_CLOSE);
 	}
 	
 }