fix: tighten stack selection keyboard handling

samples/dev/index.js

@@ -114,7 +114,7 @@ function moveStackSelection(direction) {
   if (!hasStackSelection()) {
     if (direction === 'up') {
       ensureValidSelection();
-    } else {
+    } else if (direction === 'down') {
       reactivateEditOnX();
     }
     return;
@@ -123,11 +123,6 @@ function moveStackSelection(direction) {
   const nextIndex = direction === 'up' ? stackCursor + 1 : stackCursor - 1;
   if (calc.isValidIndex(nextIndex)) {
     stackCursor = nextIndex;
-    return;
-  }
-
-  if (direction === 'down' && stackCursor === 0) {
-    reactivateEditOnX();
   }
 }
 
@@ -352,6 +347,13 @@ function handleKeydown(event) {
       if (isMovingStackItem) {
         event.preventDefault();
         cancelMoveMode();
+        clearStackSelection();
+        render();
+        return;
+      }
+      if (hasStackSelection()) {
+        event.preventDefault();
+        clearStackSelection();
         render();
       }
       return;