Fixes#7972.
## Thinking Path
- The reporter pinned the post-submit composer-viewport restore in
`ui/src/lib/issue-chat-scroll.ts`, which falls back to
`window.scrollBy(...)` when `#main-content` is not independently
scrollable — exactly the short-thread repro case.
- In the desktop shell the body is `overflow: hidden` (set in
`Layout.tsx`) inside a fixed-height `h-dvh` flex column, so a window
scroll never moves content: it translates the entire shell (sidebar
included) off-screen, and a plain reload does not restore it. On mobile
(`min-h-dvh`, `body { overflow: visible }`) and the auth-free perf
fixture the page genuinely scrolls, so the window IS the correct target
there.
- A prior attempt forced `resolveIssueChatScrollTarget` to always use
`#main-content`; that path is a no-op on a non-overflowing container and
is sensitive to a stale `ui/dist`/`.vite` cache, which likely masked the
result. Gating the window-scroll itself is the precise root-cause fix
and covers both restore call sites (`queueViewportRestore` and the
`[messages]` layout effect) since both route through one function.
## What Changed
- Added `isWindowScrollable(doc, win)` to `issue-chat-scroll.ts`: the
window is a valid scroll target only when the document body is not
clipped. It checks both the `overflow` shorthand and the `overflow-y`
longhand (some engines, incl. jsdom, do not derive the longhand from the
shorthand in computed style).
- Gated the `window.scrollBy` fallback in
`restoreComposerViewportSnapshot` behind `isWindowScrollable`; on the
desktop shell there is nothing to restore, so the scroll position is
left untouched.
- Added unit tests for the desktop-shell (no window scroll) case and for
`isWindowScrollable`.
## Verification
- `ui $ vitest run src/lib/issue-chat-scroll.test.ts` → 6 passed (2 new
+ existing window/element restore tests still green).
- `ui $ vitest run src/components/IssueChatThread.test.tsx` → 55 passed
(consumer regression).
## Risks
- Low. Behaviour only changes when the resolved target is `window` AND
the document body is clipped — i.e. the desktop shell, where the
previous behaviour was the bug. Mobile and the perf fixture keep window
scrolling unchanged (body not clipped → `isWindowScrollable` true).
## Model Used
claude-opus-4-8
---
- [x] I searched the GitHub PRs for similar or duplicate PRs and
confirmed this is not a duplicate.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
## Thinking Path
> - Paperclip orchestrates AI agents for zero-human companies
> - A core part of that is the operator experience around reading issue
state, agent chat, and sub-task structure
> - The current branch had a long run of issue-detail and issue-list UX
fixes that all improve how humans follow and steer active work
> - Those changes mostly live in the UI/chat surface and should be
reviewed together instead of mixed with workspace/runtime work
> - This pull request packages the issue-detail, chat, markdown, and
sub-issue list improvements into one standalone change
> - The benefit is a cleaner, less jumpy, more reliable issue workflow
on desktop and mobile without coupling it to unrelated server/runtime
refactors
## What Changed
- Stabilized issue chat runtime wiring, optimistic comment handling,
queued-comment cancellation, and composer anchoring during live updates
- Fixed several issue-detail rendering and navigation regressions
including placeholder bleed, local polling scope, mobile inbox-to-issue
transitions, and visible refresh resets
- Improved markdown and rich-content handling with advisory image
normalization, editor fallback behavior, touch mention recovery, and
`issue:` quicklook links
- Refined sub-issue behavior with parent-derived defaults, current-user
inheritance fixes, empty-state cleanup, and a reusable issue-list
presentation for sub-issues
- Added targeted UI tests for the new issue-detail, chat scroll/message,
placeholder-data, markdown, and issue-list behaviors
## Verification
- `pnpm vitest run ui/src/components/IssueChatThread.test.tsx
ui/src/components/MarkdownEditor.test.tsx
ui/src/components/IssuesList.test.tsx
ui/src/context/LiveUpdatesProvider.test.tsx
ui/src/lib/issue-chat-messages.test.ts
ui/src/lib/issue-chat-scroll.test.ts
ui/src/lib/issue-detail-subissues.test.ts
ui/src/lib/query-placeholder-data.test.tsx
ui/src/hooks/usePaperclipIssueRuntime.test.tsx`
## Risks
- Medium: this branch touches the highest-traffic issue-detail UI paths,
so regressions would show up as chat/thread or sub-issue UX glitches
- The changes are UI-heavy and would benefit from reviewer screenshots
or a quick manual browser pass before merge
## Model Used
- OpenAI Codex coding agent (GPT-5-class runtime in Codex CLI; exact
deployed model ID is not exposed in this environment), reasoning
enabled, tool use and local code execution enabled
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [ ] If this change affects the UI, I have included before/after
screenshots
- [ ] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
Doyeon Baek
Dotta