Some filter rules suddenly stopped working

[bdr99]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT an issue with YouTube, Facebook or Twitch.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

I noticed that recently, certain filter rules are no longer being applied, for seemingly no reason.

For example, EasyList contains this rule which is supposed to remove ads on Reddit:

reddit.com,reddittorjg6rue252oqsxryoxengawnmo46qy4kyii5wtqnwfj4ooad.onion##.promotedlink:not([style^="height: 1px;"])

But when I navigate to a Reddit page that contains ads, such as https://old.reddit.com/r/uBlockOrigin/, I still see the "promoted" posts. If I check the logger, the rule is shown and highlighted in yellow, which I believe means it should have been applied.

I have tried the following:

Attempted Solution	Outcome
Disabled all add-ons except uBO	No change.
Reset uBO using the "Reset to default settings" button	No change.
Used a new unmodified browser profile	This does fix the issue, but I'm trying to fix it on my existing browser profile.
Added the above filter rule to "My filters"	No change.
Unchecked "Parse and enforce cosmetic filters"	No change.
Added the rule to "My filters" AND unchecked "Parse and enforce cosmetic filters"	This works and the rule is applied correctly.
Held shift, clicked "Purge all caches", then updated filter lists.	No change.
Uninstalled and reinstalled uBO.	No change.

A specific URL where the issue occurs.

https://old.reddit.com/r/uBlockOrigin/

Steps to Reproduce

1. Install uBO with default settings and filter lists.
2. Navigate to https://old.reddit.com/r/uBlockOrigin/.

Expected behavior

Promoted posts should not be visible.

Actual behavior

Promoted posts are visible.

uBO version

1.54.0

Browser name and version

Firefox 121.0

Operating System and version

Windows 11

Please share your troubleshooting information. Go to Reddit, click uBO icon on toolbar, the "chat" button, "Troubleshooting Information" at the bottom, select all and copy here.

[bdr99]

@gwarser Thanks for the reply, here is my troubleshooting info:

uBlock Origin: 1.54.0
Firefox: 121
filterset (summary):
 network: 104575
 cosmetic: 44290
 scriptlet: 18655
 html: 1978
listset (total-discarded, last-updated):
 default:
  user-filters: 0-0, never
  ublock-filters: 37241-151, 12h.10m
  ublock-badware: 7569-11, 12h.10m
  ublock-privacy: 948-4, 12h.10m
  ublock-unbreak: 2222-1, 12h.10m
  ublock-quick-fixes: 152-0, 12h.10m
  easylist: 76499-670, 12h.10m
  easyprivacy: 33170-811, 12h.10m
  urlhaus-1: 9710-0, 12h.10m
  plowe-0: 3784-1, 12h.10m
filterset (user): [empty]
userSettings: [none]
hiddenSettings: [none]
supportStats:
 allReadyAfter: 318 ms
 maxAssetCacheWait: 131 ms
popupPanel:
 blocked: 12
 network:
  reddit.com: 9
  ad-delivery.net: 1
  redditmedia.com: 1
  redditstatic.com: 1
 extended:
  ##a.outbound[data-outbound-url]:remove-attr(data-outbound-url)
  ##+js(abort-on-property-write, STICKY_CANARY)

Can you reapeat the logging and click the .promotedlink... filter to see details? Does it tell the filter is from EasyList?

Try if clicking "Purge all caches" with Shift pressed and the updating filter lists improves something.

[bdr99]

@gwarser

This is what I see if I click on the filter in the logger.

I tried holding shift and clicking "Purge all caches" and then updating the filter lists, but this didn't help unfortunately. I also tried uninstalling uBO entirely and installing it again, but this didn't help either.

If you switch the logger to DOM inspector (the </> button in top right) did you see the .promotedlink... filter blocking something?

I think it's Reddit doing some A/B testing.

---

Crosslinking https://www.reddit.com/r/uBlockOrigin/comments/18um5lm/promoted_ads_have_started_appearing_on_reddit_for/

[bdr99]

If you switch the logger to DOM inspector (the </> button in top right) did you see the .promotedlink... filter blocking something?

If I click on the DOM inspector button, I actually just get a blank screen.

I think it's Reddit doing some A/B testing.

But the strange part is that (as mentioned in the issue description) if I add that same exact rule to "my filters", it works (as long as I also uncheck "Parse and enforce cosmetic filters").

[u-RraaLL]

Install dev build and test: https://github.com/gorhill/uBlock/releases/tag/1.54.1rc1

To install click the signed firefox file. Proceed with accepting, then right-click uBO icon > Manage extension > Update now.

[bdr99]

@u-RraaLL No change, I still get the same issue with 1.54.1rc1.

[bdr99]

Also, I checked the DOM, and I can see that the reddit ad div still has the promotedlink CSS class. So it definitely seems like it should still match that rule.

[gorhill]

Maybe one invalid cosmetic filter being injected is breaking all others. Would need to find which cosmetic filter from which list.

[gorhill]

To help narrow the problematic cosmetic filter, first, try:

@@||reddit.com^$ghide

This will tell us whether the problematic filter is generic or specific.

---

Also, looking at the page logger dev tools console when enabling dom inspector might show an selector error being reported.

[bdr99]

Maybe one invalid cosmetic filter being injected is breaking all others. Would need to find which cosmetic filter from which list.

When I test with a clean Firefox profile, I don't see this issue. Wouldn't this indicate that it isn't caused by a filter rule?

To help narrow the problematic cosmetic filter, first, try:

@@||reddit.com^$ghide

This will tell us whether the problematic filter is generic or specific.

I added this rule to "My rules" but there was no change, I still see the ad.

Also, looking at the page logger dev tools console when enabling dom inspector might show an selector error being reported.

It doesn't look like there is any output in the logger dev tools console when enabling the DOM inspector.

[gorhill]

Used a new unmodified browser profile
his does fix the issue, but I'm trying to fix it on my existing browser profile.

Did you set layout.css.has-selector.enabled to false in about:config? I can reproduce all your symptoms when setting it to false. It defaults to true as of Firefox 121.

[garry-ut99]

bdr99 : #3050 (comment) : But the strange part is that (as mentioned in the issue description) if I add that same exact rule to "my filters", it works

Nothing strange, it's by design, unchecking this option disables all cosmetic filters in all filter lists, except "My Filters pane", that's why your filter still works, like already mentioned in :

• Allow My Filter to override Ignore generic cosmetic filters #821 (comment)
• https://github.com/uBlockOrigin/uBlock-issues/wiki/Dashboard:-Filter-lists#parse-and-enforce-cosmetic-filters,

---

bdr99 : #3050 (comment) : (as long as I also uncheck "Parse and enforce cosmetic filters").

Why it works only after disabling cosmetic filters in all lists, is another story, maybe because like gorhill already said : maybe one of lists/filter breaking the other.

gorhill : #3050 (comment) : Maybe one invalid cosmetic filter being injected is breaking all others. Would need to find which cosmetic filter from which list.

Similiar to the old story (but this time in Firefox) :

• Cosmetic filters not working on many websites with "Experimental Web Platform features" in chrome://flags #1751

[gorhill]

If reddit.com##.promotedlink:not([style^="height: 1px;"]) works in "My filters", then add reddit.com##.size-compact.Post:has([class*="promoted"]) and see if the issue comes back.