Bug description

When using Unpoly modals together with Tabler (Bootstrap 5 based UI kit), the page scroll position jumps upward when the modal opens. Workaround/fix is provided below. I'm not sure if this is an Unpoly bug.

Reproduction project

Minimal reproducible demo:
https://stackblitz.com/edit/empty-unpoly-project-x4dpyzvf?file=index.html

Steps to reproduce the behavior:

1. Go to reproduction project linked above.
2. Scroll down the page.
3. Click on the "Open modal" button.

Expected behavior

Opening a modal should not change the page scroll position.

Browser version

Latest Chrome, Safari on macOS.

Additional context

Fix/workaround:

<style>
:root { height: auto; }
.page { min-height: 100vh; }
</style>