diff --git a/samples/dev/index.html b/samples/dev/index.html
index 08e168b..c892ca2 100644
--- a/samples/dev/index.html
+++ b/samples/dev/index.html
@@ -330,7 +330,14 @@
 
     function execute(name) {
       try {
-        if (name === 'swap') {
+        if (name === 'enter') {
+          if (calc.isEditing) {
+            pushEditingValueIfNeeded();
+          } else if (calc.stack.length >= 1) {
+            calc.push(calc.stack[0]);
+            if (calc.stack.length > 4) calc.stack.length = 4;
+          }
+        } else if (name === 'swap') {
           pushEditingValueIfNeeded();
           if (calc.stack.length >= 2) calc.swap(0, 1);
         } else if (name === 'drop') {