Repository: vscode
Issue: Flickering on scaled ultrawide monitor on M3 Pro Mac
Labels: info-needed

Type: <b>Bug</b>

Random parts of the VS Code window flicker when typing / scrolling.

https://github.com/microsoft/vscode/assets/813661/f208c708-0c2f-429b-870c-b9a738dfa142

https://github.com/microsoft/vscode/assets/813661/4cb1e107-5b78-4747-8cd3-0d292bd40c73

https://github.com/microsoft/vscode/assets/813661/bd6d8993-6f25-4f2c-8bfc-bbd77f677d2a


Steps to Reproduce:

1. External screen with native resolution of 5120x2160 (Dell U4025QW)
2. Setup scaled resolution of 3840x1620. This is OS scaling, the monitor still reports a native resolution of 5120x2160.
3. Open VSCode with all extensions disabled, and default settings (json settings emptied).
4. Open several files side by side, optionally using "diff mode". The more visible editors, the more the error is likely to appear.


Note:

- This is not linked to dark colors as described in other issues. (Issue occurs when OS is in light mode, with a light theme)
- Scrolling while VS Code is *not* focussed does not trigger the issue
- Happens both in full screen mode and non-fullscreen mode


Similar issues:

- https://github.com/microsoft/vscode/issues/193908
- https://github.com/microsoft/vscode/issues/165681


Workaround:

- Disable HiDPI scaling in OS and use VS Code's window zoom. This affects all apps, making it not suitable.
- Set `"disable-hardware-acceleration": true,` in  `Preferences: Configure Runtime Arguments`.

VS Code version: Code 1.90.2 (5437499feb04f7a586f677b155b039bc2b3669eb, 2024-06-18T22:54:35.075Z)
OS version: Darwin arm64 23.5.0
Modes:

<details>
<summary>System Info</summary>

|Item|Value|
|---|---|
|CPUs|Apple M3 Pro (12 x 2400)|
|GPU Status|2d_canvas: unavailable_software<br>canvas_oop_rasterization: disabled_off<br>direct_rendering_display_compositor: disabled_off_ok<br>gpu_compositing: disabled_software<br>multiple_raster_threads: enabled_on<br>opengl: disabled_off<br>rasterization: disabled_software<br>raw_draw: disabled_off_ok<br>skia_graphite: disabled_off<br>video_decode: disabled_software<br>video_encode: disabled_software<br>webgl: unavailable_software<br>webgl2: unavailable_software<br>webgpu: unavailable_software|
|Load (avg)|2, 2, 2|
|Memory (System)|36.00GB (0.30GB free)|
|Process Argv|--crash-reporter-id b9f963fa-db84-4aac-9a3d-85fa771e9805|
|Screen Reader|no|
|VM|0%|
</details><details><summary>Extensions (28)</summary>

Extension|Author (truncated)|Version
---|---|---
lit-html|bie|1.11.1
vscode-tailwindcss|bra|0.12.3
npm-intellisense|chr|1.4.5
postcss|css|1.0.9
vscode-eslint|dba|3.0.10
eslint-disable-snippets|drK|1.4.1
gitlens|eam|15.1.0
EditorConfig|Edi|0.16.4
prettier-vscode|esb|10.4.0
vscode-firefox-debug|fir|2.9.10
vscode-jest-runner|fir|0.4.73
copilot|Git|1.208.0
copilot-chat|Git|0.16.1
copy-github-url|mat|0.14.0
import-sorter|mik|3.3.1
dotenv|mik|1.0.1
ecdc|mit|1.8.0
hexeditor|ms-|1.10.0
sublime-keybindings|ms-|4.1.10
vscode-typescript-next|ms-|5.6.20240701
one-dark-theme|msk|1.14.2
material-icon-theme|PKi|5.4.2
rewrap|stk|17.8.0
code-spell-checker|str|3.0.1
sort-lines|Tyr|1.11.0
highlight-bad-chars|wen|0.0.6
change-case|wma|1.0.0
markdown-all-in-one|yzh|3.6.2


</details><details>
<summary>A/B Experiments</summary>

```
vsliv368cf:30146710
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscoreces:30445986
vscod805cf:30301675
binariesv615:30325510
vsaa593cf:30376535
py29gd2263:31024239
c4g48928:30535728
azure-dev_surveyone:30548225
a9j8j154:30646983
962ge761:30959799
pythongtdpath:30769146
welcomedialog:30910333
pythonnoceb:30805159
asynctok:30898717
pythonregdiag2:30936856
pythonmypyd1:30879173
2e7ec940:31000449
pythontbext0:30879054
accentitlementsc:30995553
dsvsc016:30899300
dsvsc017:30899301
dsvsc018:30899302
cppperfnew:31000557
dsvsc020:30976470
pythonait:31006305
jchc7451:31067544
chatpanelc:31048052
dsvsc021:30996838
g316j359:31013175
pythoncenvpt:31062603
a69g1124:31058053
dvdeprecation:31068756
dwnewjupytercf:31046870
newcmakeconfigv2:31071590
impr_priority:31082723

```

</details>

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