fix: sticky header needs overflow-y-auto parent, textarea auto-resize on preview toggle, markdown source always visible

memento-note/components/note-editor.tsx

@@ -266,6 +266,20 @@ export function NoteEditor({ note, readOnly = false, onClose, fullPage = false }
     el.style.height = Math.max(el.scrollHeight, 280) + 'px'
   }, [content])
 
+  // Also auto-grow when switching FROM preview TO edit mode
+  useEffect(() => {
+    if (showMarkdownPreview) return // we're in preview, textarea not mounted
+    // Defer one frame so the textarea is in the DOM
+    const raf = requestAnimationFrame(() => {
+      const el = textareaRef.current
+      if (!el) return
+      el.style.height = 'auto'
+      el.style.height = Math.max(el.scrollHeight, 280) + 'px'
+      el.focus()
+    })
+    return () => cancelAnimationFrame(raf)
+  }, [showMarkdownPreview])
+
   const handleRemoveImage = (index: number) => {
     const removedUrl = images[index]
     setImages(images.filter((_, i) => i !== index))