# \[Bug\]: Scrolling lists in dialogs flickers on macOS, but never while screen recording · Issue \#23788 · pingdotgg/t3code

[View on GitCafe](https://git.cafe/pingdotgg/t3code/issues/23788)

Repository: [pingdotgg/t3code](https://git.cafe/pingdotgg/t3code)

Visibility: public

State: backlog

Priority: 0

## Description

[Discussion and activity](https://git.cafe/pingdotgg/t3code/issues/23788)

---

### Before submitting

- [x] I searched existing issues and did not find a duplicate.
- [x] I included enough detail to reproduce or investigate the problem.

Possibly related: #7766 (flicker over masked scroll areas on Linux and Windows). For those reporters, removing the `scroll-area-viewport` mask fixes it. Here it doesn't, so I'm filing this separately until we know whether it's the same root cause.

### Area

apps/desktop

### Steps to reproduce

1. On macOS, open T3 Code (Nightly).
2. Go to Settings → Providers → Add provider.
3. Scroll the "Or choose from ACP Registry" list.

The same flicker happens when scrolling the command palette.

### Expected behavior

The list scrolls without flickering.

### Actual behavior

The dialog flickers while the list scrolls. **It never shows up while macOS screen recording is running**, so I haven't been able to capture it in a recording.

Ruled out with live DevTools overrides in Nightly (none of these stopped the flicker):

- `mask-image: none` on `[data-slot=scroll-area-viewport]`. This doesn't touch the command palette's mask, which is `.virtualized-scroll-fade` on the LegendList scroller.
- A static mask on the viewport, and the mask moved to the non-scrolling ScrollArea root.
- `filter: none` on the registry icons, which use an SVG `url(#…)` filter.
- `backdrop-filter: none` on `dialog-popup` and `dialog-backdrop`.
- `will-change: auto` on the popup.

I also probed it headlessly against a dev server in Linux Chromium, and over CDP in Chrome 155 on another Mac (DPR 1 and 2), using real wheel ticks. In neither dialog did anything change on every frame: no React commits, no layout shift, and on macOS no GPU layers created or destroyed. The only per-frame repaint was the scrollbar thumb. React only commits at scroll start and stop (`data-scrolling`). The scrollbar's opacity transition never runs during a wheel scroll, because `data-hovering` stays set.

The one per-frame churn found was in Linux Chromium at DPR 1: the mask makes a large "Overlap" layer get rebuilt on almost every wheel tick (~21 per gesture, 0 with the mask removed). It doesn't happen on macOS at DPR 1 or 2.

Current guess: a Chromium compositor or macOS display-timing bug, possibly ProMotion frame pacing, which would explain why screen recording hides it. Unconfirmed.

Not yet tried:

- Disabling all masks, filters, backdrop filters, transitions and animations at once.
- Hiding the scrollbars.
- Locking the display to 60 Hz.
- Launching with `--disable-skia-graphite` or `--disable-gpu-compositing`.

### Impact

Cosmetic issue

### Version or commit

T3 Code (Nightly), Electron 44.4.5

### Environment

macOS, T3 Code (Nightly) desktop app

### Workaround

None found yet.