Can be reproduced on Chromium 67(current stable) too.

Firefox says:

Content Security Policy: The report URI (about:blank) should be an HTTP or HTTPS URI.

That's normal, Firefox expects a URL instead of about:blank. Also this issue is specific to Chromium, so don't remove the Chromium lable.

I don't think it's a Chromium specific issue. I could never see the white dotted icon on Firefox.

The white dotted icon does appear for me on Firefox Nightly - https://i.gyazo.com/5b9fc6b531dcc71e1fc6db25c23da306.png

Also the issue here is limited to specific listed URL only for Chromium, the white dotted icon does appear normally on all other web pages where workers are deployed.

Odd because it doesn't show for me in v61 latest Firefox beta screenshot taken while the counter is running: https://i.imgur.com/mfsiN99.jpg

I've tried to get the white dotted icon to appear in the past when it was added as a feature but I have never seen the dot even on other websites using web workers so I assumed it didn't show because of something with my Firefox setup. But the above image is in a pretty clean profile so unless it was recently fixed in Nightly I don't know.

Anyone else on stable/beta Firefox that can check if the white dotted icon shows for them?

I could never see the white dotted icon on Firefox.

In about:config, you need to toggle security.csp.enable_violation_events to true. I confirm the issue does not affect Firefox.

Thanks gorhill, now I can see it. I'm guessing the config value is turned on by default in Nightly then.

@gorhill https://bugs.chromium.org/p/chromium/issues/detail?id=996659

is that relevant to this bug ?

@gorhill Regression in v1.4.1b0 on Firefox, it doesn't display white dotted icon for the Forbid Web Workers switch, neither a blocked entry is seen in the logger.

additional test url- https://mdn.github.io/simple-web-worker/

Edit: White dotted icon for three switches is broken -- Forbid mixed content/Forbid web workers/Spoof noscript tags. Tested at https://www.bennish.net/mixed-content.html