## Summary
- Run-view inspector panel was glitching out on Firefox: visual flicker
on close, locking up at min size, and intermittent `panelHasSpace`
invariant errors. Root cause is the underlying `react-window-splitter`
library's collapse animation, which uses `@react-spring/rafz` and
interacts poorly with Firefox.
- Disabled the library's collapse animation on Firefox only, app-wide
(every consumer of `RESIZABLE_PANEL_ANIMATION`). Chromium and Safari
behaviour is unchanged.
## Changes
- **Firefox animation skip** in `RESIZABLE_PANEL_ANIMATION` —
UA-detected at module load, resolves to `undefined` for Firefox so the
library's animation actor completes in one frame instead of running its
rAF loop.
- **Inspector min raised 50px → 250px** so dragging can't shrink the
panel into a near-useless width.
- **`autosaveId` bumped `v2` → `v3`** to invalidate stale persisted
snapshots (the library has a `// TODO` branch that ignores prop changes
for already-registered panels, so existing users would otherwise still
see the old 50px min).
- **`react-window-splitter` pinned** to exact `0.4.1` to protect the
patch from drifting if line offsets change in a patch release.
- **Two hunks added to the existing `@window-splitter/state` patch:**
- Removed the library's auto-collapse-on-drag block entirely. Every
collapsible panel in the app is parent-controlled, and that block was
triggering state-machine deadlocks when handlers were no-ops.
Drag-to-collapse is now disabled across the app; collapse is only
triggered explicitly (close button, ESC, URL change, etc.).
- In `getDeltaForEvent`, fall back to the panel's `default` before its
`min` when expanding — so the first ever click on a span opens the
inspector at 500px, not 250px.
## Local testing confirmed
- [x] Firefox: open a run, click various spans → panel opens instantly
at 500px, drags freely between 250px and max, closes instantly to 0. No
console errors.
- [x] Chrome/Chromium: same flow, but with smooth open/close animation
as before.
- [x] Safari: same as Chrome.
- [x] Reload mid-session → panel restores cleanly to the dragged size.
- [x] Other resizable panels in the app (logs, deployments, schedules,
batches, bulk-actions, runs index) still animate on Chromium/Safari.
## Notes
- Linear: TRI-8584
- Branch contains intermediate commits exploring an unsuccessful
snapshot-validator approach; they're reverted by the final commit.
Cumulative diff is 6 files. Squash on merge if you'd prefer a clean
history.
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
James Ritchie