Fix: autocomplete popup mispositioned when textarea is scrolled (scro…

[tricksterzero]

Summary

The autocomplete suggestion list appears pinned to the bottom of the viewport instead of near the caret when the prompt textarea has been scrolled down.

Root cause

In #getCaretCoordinates() (web/js/autocomplete.js), the viewport conversion adds the element's scroll offset instead of subtracting it.

span.offsetTop / offsetLeft are offsets in the element's content coordinate space. Converting them to viewport coordinates requires subtracting element.scrollTop / scrollLeft, but the current code adds them. As the textarea is scrolled down, the computed caret Y grows, so #updatePosition()'s vertical-collision logic falls back and places the list near the bottom of the screen.

Fix

Before:

coordinates.top = rect.top + element.scrollTop + coordinates.top;
coordinates.left = rect.left + element.scrollLeft + coordinates.left;

After:

coordinates.top = rect.top - element.scrollTop + coordinates.top;
coordinates.left = rect.left - element.scrollLeft + coordinates.left;

This matches the reference implementation (component/textarea-caret-position), which subtracts the scroll offset.

Reproduction

1. Scroll a prompt textarea down.
2. Trigger autocomplete. => The list appears at the bottom of the screen. With an unscrolled textarea it is positioned correctly.

Verification

After the change, the popup tracks the caret regardless of scroll position. Tested on Windows. Frontend-version-independent: reproduced on both the latest and an older comfyui-frontend-package, so this is unrelated to #73.