diff --git a/cs623/proj1/RetirementCalculator.java b/cs623/proj1/RetirementCalculator.java
index 750e146..37b161e 100644
--- a/cs623/proj1/RetirementCalculator.java
+++ b/cs623/proj1/RetirementCalculator.java
@@ -9,7 +9,9 @@ import java.util.*;
  * This allows the java class to be run as a stand-alone application or
  * as an applet within a web browser.
  */
-class RetirementCalculatorPanel extends JPanel implements ActionListener
+class RetirementCalculatorPanel
+    extends JPanel
+    implements ActionListener, FocusListener
 {
     private RetirementCalculatorModel myModel;