Windows: Select box background flickers when opened

[dbaeumer]

• VSCode Version: Insider 1.12
• OS Version: Windows
• Theme: dark+

Steps to Reproduce:

1. open a workspace
2. open output channel
3. open the channel selector box

Observe: the box ix quickly render with a white / light background before it is rendered using a dark background.

[bpasero]

I see the same in stable, could be an upstream thing though that we cannot fix.

[bpasero]

Tried a few things (e.g. disabled transition on the action-item), but with no luck. If someone has an idea, help welcome.

[the-ress]

It seems to be a bug in Chromium. I reduced it to a simple HTML: https://codepen.io/anon/pen/pPdKPZ and it flickers in the latest Chrome, even in the canary build. (It flickers less often there, but it can still be reliably reproduced using CPU throttling in dev tools.)

I reported it here: https://bugs.chromium.org/p/chromium/issues/detail?id=719255

[bpasero]

@the-ress thanks!

[bpasero]

On Windows and Linux we are now using custom select box (via #37533)