The open list of CategoryCombobox was positioned `absolute` inside its
input's container, so a scrolling ancestor clipped it: the body of the
split window, the `overflow-x-auto` wrapper of the Transactions table.
It is now rendered in a portal on document.body, `position: fixed`, at
z-[300] (above every window, the highest at z-[210]).
The pure rule lives in placeListbox.ts: under the input, as wide as it,
4 px below; above it when the room below is short of the list's 240 px
and the room above has them; below when neither side has them. The
list is placed in a layout effect before the first paint, then follows
the input on every scroll (capture phase, any scrolling container) and
resize while it is open, skipping scrolls of the list itself; the
listeners are removed with the list (followAnchor returns the cleanup).
The outside press counts the list as inside, since it no longer sits in
the container's DOM. The closed markup is unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
