The scroll body holds [nav, RECENTS header, RECENTS], and RECENTS carries the
only stretch factor. Collapsing hides it, which leaves a fixed-height nav tree
(app.py sets one per row count) and nothing that can expand — so the box layout
centred what was left and the destinations dropped 297px down a 1048px window,
with the same gap opening below them.
A stretch spacer at the foot of the body takes the slack instead. It takes none
of it while RECENTS is visible, because RECENTS carries stretch 1 against its 0,
so the open rail is byte-for-byte what it was.
This is what "thu gọn menu lại ra giữa" meant, reported three times. I read it
as horizontal each time and measured x — which was 4px and correct throughout.
The report was about the vertical axis and I never checked it.
check_rail_align now measures the gap between the ＋ button and the first
destination in both states: 6px/6px now, 6px/223px with the spacer removed.
15/15 checkers pass.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
