diff --git a/samples/dev/index.js b/samples/dev/index.js
index ce86fa2..36e40bc 100644
--- a/samples/dev/index.js
+++ b/samples/dev/index.js
@@ -143,23 +143,28 @@ function moveStackItem(direction) {
 function render() {
   const names = ['T', 'Z', 'Y', 'X'];
   const lines = [];
+  const showStackIndexes = hasStackSelection() || isMovingStackItem;
+
   for (let line = 3; line >= 0; line -= 1) {
     const value = getLineValue(line);
     const isSelected = stackCursor === line;
     const classes = ['stack-line'];
+    const label = showStackIndexes ? String(line) : names[3 - line];
+
     if (isSelected) {
       classes.push(isMovingStackItem ? 'moving' : 'selected');
     }
-    lines.push(`<div class="${classes.join(' ')}"><div class="label">${names[3 - line]}</div><div>${value !== undefined && value !== '' ? calc.formatNumber(value) : ''}</div></div>`);
+
+    lines.push(`<div class="${classes.join(' ')}"><div class="label">${label}</div><div>${value !== undefined && value !== '' ? calc.formatNumber(value) : ''}</div></div>`);
   }
 
   stackEl.innerHTML = lines.join('');
   if (calc.isEditing) {
     displayEl.textContent = `ENTERING: ${calc.inputValue}`;
   } else if (isMovingStackItem && hasStackSelection()) {
-    displayEl.textContent = `MOVING: ${['X', 'Y', 'Z', 'T'][stackCursor] || '?'}`;
+    displayEl.textContent = `MOVING: ${stackCursor}`;
   } else if (hasStackSelection()) {
-    displayEl.textContent = `SELECTED: ${['X', 'Y', 'Z', 'T'][stackCursor] || '?'}`;
+    displayEl.textContent = `SELECTED: ${stackCursor}`;
   } else {
     displayEl.textContent = 'READY';
   }