Textarea - Growing height as content grows

[enriquemorenotent]

I noticed that on the website, the textarea automatically expands as its content grows:

Screencast.from.2025-10-20.16-32-53.webm

However, when I try to reproduce this behavior locally, the textarea keeps a fixed height and shows a scrollbar instead.

Could someone clarify how this auto-growing behavior is implemented on the site?
Is it part of the shadcn/ui system itself, or does it rely on an external library or custom code? If external, which one?

[tonghohin]

just don't put a fixed height on the textarea

[enriquemorenotent]

Even without the fix height, it still doesn't grow.