Rendering issues in Flutter docs portal in chrome when Local Network Access is blocked

[amarghosh]

Page URL

https://docs.flutter.dev/app-architecture/design-patterns/result

Page source

https://github.com/flutter/website/blob/main/src/content/app-architecture/design-patterns/result.md

Describe the problem

Chrome recently started showing a popup asking for "local network access" whenever you load certain websites, flutter docs being one of them. I instinctively click Block on these popups. It turns out some CSS features like chevrons and list icons throughout the flutter docs portal are not displayed properly unless local network access is granted. The page shows the alt-text chevron_right instead of the chevron image. I know it sounds crazy, but I have verified this by granting and blocking this permission from the site settings option under Chrome settings. This was seen on Chrome on Mac with version 144.0.7559.110 (Official Build) (x86_64). I have attached a screenshot that shows the issue.

Expected fix

No response

Additional context

• Chrome 144.0.7559.110 (Official Build) (x86_64)
• MacOS 15.6.1
• Issue seen across the docs.flutter.dev portal

I would like to fix this problem.

• I will try and fix this problem on docs.flutter.dev.

[sfshaza2]

Ack!

[schultek]

So far no luck with replicating this. I'm on Chrome Version 144.0.7559.110 (Official Build) (arm64)

I'm not even getting the permission popup, but I'm also unsure what could trigger this.
@amarghosh Could you try deactivating any chrome extensions you have or trying on a guest profile in chrome?

[amarghosh]

I am able to trigger the popup (and the issue) by merely loading a flutter docs page in the incognito mode. I am assuming the extensions are unavailable in incognito mode. Screenshot of the popup attached. The page wouldn't start loading until I click Block or Allow. And the issue is seen when I block it. As far as I know, this popup started appearing in Chrome v142.

[parlough]

Thanks for the extra info. I also can't reproduce this either.

Do you have some sort of proxy set up for Google-related sites (such as googleapis.com or fonts.gstatic.com)?

Or are you using your computer and router's default DNS setup or have some custom setup? Can you try using Google DNS or Cloudflare's 1.1.1.1 DNS?

[amarghosh]

Wait a sec.. I just remembered that I have zscaler installed on my Mac. That might be doing god knows what behind the scenes! That could be the reason why I am getting this popup and you're not. I checked this issue from my colleagues' machines as well, but they all have zscaler. If this is not happening on non-zscaler Macs, we can safely ignore this, right?

[parlough]

Thanks for the extra information @amarghosh!

I definitely imagine tools like zscaler could cause this new prompt to occur. https://trust.zscaler.com/private.zscaler.com/posts/26216 seems to confirm this. From that post, it seems your company should make some adjustments to shared Chrome/Edge policies to avoid this occurring across various sites going forward. Perhaps you can share that link with your IT department.