fix(cmux-next sidebar): the icon rail keeps its 48px column (it shared .acpmux-rail with the session rail)
Layout pass, running list (full list in cmuxterm-hq knowledge/layout-pass.md):
- Merged: #22785 Settings, #22825 Markdown, #22839 Chief inspector, #22847 Harnesses, #22862 Settings in the gallery, #22872 Code editor find, #22880 gallery picker Tailwind, #22897 diff toolbar, #22904 Passwords, #22917 Agent Activity, #22954 Stats, #22959 Path picker, #22966 History
- Open: #22976 App Store, #23002 session sidebar "No matching chats", this PR: session sidebar icon rail
Summary
The chats sidebar's icon rail and the chat's session rail (summary/SessionRail.tsx) both used the class .acpmux-rail. Where summary.css loads after the sidebar's styles.css (the pane's dev.tsx entry, and the gallery), the session rail's rules won:
- its
flex: 0 0 clamp(240px, 26%, 340px)column; - under 560px, its absolute 300px overlay.
So the 48px icon rail drew 268 to 300px wide, and the chat list was squeezed to 32 to 80px. The sidebar's rail is now .acpmux-sidebar-rail: in the markup, its rule in styles.css, the prototype's .proto-history hide rule, and the gallery anchor. The session rail keeps .acpmux-rail.
Before / after
Gallery agent-pane.session-sidebar / baseline. Measured rail x and width: before, 32/268 at 300 and 220/300 at 520; after, 0/48 at both.
| Before | After | |
|---|---|---|
| 300, dark |  |  |
| 520, light |  |  |
(The "No matching chats" line in both shots is a separate bug, fixed by #23002.)
Test
cd webviews && bun test test/sidebar-rail-css.test.tsx loads both sheets into happy-dom, renders the sidebar, and reads the icon rail's computed style.
- Base (red commit e9c4f500b6e): fails with
["stretch", "2px"]instead of["center", "0px"](the session rail'salign-itemsand padding). - Head: passes.
Observed / Not run
- Ran: the test above (red, then green). Also ran
session-rail,chats-sidebar-empty,session-sidebar-previewandchat-rows-open-on-press(25 pass), oxfmt, oxlint, tsc (no errors in the changed files),check:{layers,type-scale,status-glyphs,system-blue,text-focus,dialog-keys,switch-fetches,browser-lanes}andprepush-gate.py. The stills come from the gallery dev server in Chromium. - Not run: the full
bun run check(it's fleet-only on huge-blue; CI runs it) and the native app.
Changelog
Fixed: The chats sidebar's icon rail no longer stretches across the sidebar and squeezes the chat list.
Agent session: huge-blue
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