User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

1. add a bookmark to a site with a valid favicon to the Bookmark toolbar
2. click on it

Actual results:

The favicon "flickers" nearly everytime. It's very annoying, especially for someone like me who utilizes bookmarks very heavily.

In this example, I click on 4 bookmarks and 3 of them exhibit this "flickering" behavior: https://i.imgur.com/ZaU2d82.mp4

Expected results:

It shouldn't "flicker", well at least not nearly this often.

I'm assuming this behavior is somewhat expected in the sense FF is actually "refreshing" the favicons to make sure they're up to date but I really don't think it's necessary to do this any way near as often as it's doing. It isn't like I'm clicking on these bookmarks every once in a while, I do so every day, sometimes in the span of 5-10 minutes and get the flickering nearly every time.

The Bugbug bot thinks this bug should belong to the 'Firefox::Bookmarks & History' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

It looks like the result of refreshing the icon after the page loads and potentially a new favicon is available.
Icons are updated every 7 days, thus ideally this should only happen once per week per icon, it's strange it's happening so often, I wonder if there's something unexpected about the cache.
Do you have add-ons or settings that may influence the HTTP cache? Could you please attach a log from about:support?

(In reply to Marco Bonardo [:mak] from comment #2)

It looks like the result of refreshing the icon after the page loads and potentially a new favicon is available.

Not sure if this helps narrow things down, but I did the same thing from my original example only with the Browser Toolbox open and it just looking at the Inspector, the icon image seems like it is being refreshed.

Icons are updated every 7 days, thus ideally this should only happen once per week per icon, it's strange it's happening so often, I wonder if there's something unexpected about the cache.
Do you have add-ons or settings that may influence the HTTP cache? Could you please attach a log from about:support?

I don't believe so. The only active addon I have at the moment is uBlock Origin v1.34.0. I tried disabling it completely and restarting FF but found the same behavior with the bookmark favicons.

As far as the about:support logs go, I don't see anything specifically mentioning "logs" on the about:support page so I'm assuming you're just looking for a the raw text itself. If so here it is:

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[
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"image.avif.enabled",
false
],
[
"experimental-features-media-jxl",
"image.jxl.enabled",
false
],
[
"experimental-features-multi-pip",
"media.videocontrols.picture-in-picture.allow-multiple",
true
],
[
"experimental-features-ime-search",
"browser.urlbar.keepPanelOpenDuringImeComposition",
false
],
[
"experimental-features-web-api-inputmode",
"dom.forms.inputmode",
false
],
[
"experimental-features-web-gpu2",
"dom.webgpu.enabled",
false
],
[
"experimental-features-webrtc-global-mute-toggles",
"privacy.webrtc.globalMuteToggles",
false
],
[
"experimental-features-win32k-lockdown",
"security.sandbox.content.win32k-disable",
false
]
],
"addons": [
{
"name": "Amazon.com",
"type": "extension",
"version": "1.3",
"isActive": true,
"id": "amazondotcom@search.mozilla.org"
},
{
"name": "Bing",
"type": "extension",
"version": "1.3",
"isActive": true,
"id": "bing@search.mozilla.org"
},
{
"name": "DuckDuckGo",
"type": "extension",
"version": "1.1",
"isActive": true,
"id": "ddg@search.mozilla.org"
},
{
"name": "eBay",
"type": "extension",
"version": "1.3",
"isActive": true,
"id": "ebay@search.mozilla.org"
},
{
"name": "Google",
"type": "extension",
"version": "1.1",
"isActive": true,
"id": "google@search.mozilla.org"
},
{
"name": "uBlock Origin",
"type": "extension",
"version": "1.34.0",
"isActive": true,
"id": "uBlock0@raymondhill.net"
},
{
"name": "Wikipedia (en)",
"type": "extension",
"version": "1.1",
"isActive": true,
"id": "wikipedia@search.mozilla.org"
},
{
"name": "No Lazyload - Local",
"type": "extension",
"version": "0.1",
"isActive": false,
"id": "no-lazyload-local@dmattera.com"
},
{
"name": "Open Image In New Tab",
"type": "extension",
"version": "1.1.0",
"isActive": false,
"id": "open-image-in-new-tab@mint.as"
},
{
"name": "Skip Netflix Intro",
"type": "extension",
"version": "1.0",
"isActive": false,
"id": "skip_netflix_intro@jonas-hellmann.de"
},
{
"name": "Utility Belt",
"type": "extension",
"version": "0.1",
"isActive": false,
"id": "ub@dmattera.com"
}
],
"features": [
{
"name": "DoH Roll-Out",
"version": "2.0.0",
"id": "doh-rollout@mozilla.org"
},
{
"name": "Firefox Screenshots",
"version": "39.0.1",
"id": "screenshots@mozilla.org"
},
{
"name": "Form Autofill",
"version": "1.0.1",
"id": "formautofill@mozilla.org"
},
{
"name": "Picture-In-Picture",
"version": "1.0.0",
"id": "pictureinpicture@mozilla.org"
},
{
"name": "Web Compatibility Interventions",
"version": "23.1.0",
"id": "webcompat@mozilla.org"
},
{
"name": "WebCompat Reporter",
"version": "1.4.2",
"id": "webcompat-reporter@mozilla.org"
}
],
"normandy": {
"addonStudies": [],
"prefRollouts": [],
"prefStudies": [],
"nimbusExperiments": [],
"remoteConfigs": []
}
}

Sorry, forgot to include a link to the new example screengrab mentioned in my last comment:

https://i.imgur.com/U2zt7kv.mp4

Hello! I have tried to reproduce the issue on MacOS 10.15 using 91.0a1(2021-07-12) but unfortunately I wasn't able to reproduce it.
Could you please answer the following questions in order to further investigate this issue?

1. Does this issue happen in the latest firefox nightly? Here is a link from were you can download it: https://www.mozilla.org/en-US/firefox/channel/desktop/
2. Does this issue happen with a new profile? Here is a link on how to create one: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles
3. Are you using any add-ons if so could you please list them?

Any idea what "No Lazyload - Local" add-on does and where it comes from?
Does the problem happen in Safe Mode? https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

I quickly skimmed through the code but couldn't find a point where we'd update the icon if the icon is not updated. I could have certainly not noticed something that requires deeper debugging, but we should exclude any possible external cause completely first.

(In reply to Marco Bonardo [:mak] from comment #6)

Any idea what "No Lazyload - Local" add-on does and where it comes from?

that is one of my own personal addons I wrote myself and have installed "locally" (i.e. From file, not from the addon store). I have had it disabled for some time now but even when it's been enabled, I don't think it could be of any consequence here seeing as it just runs a single content-script on a handful of sites (none of which are included in any of my bookmarked sites). it just tries to undo some of the custom lazy loading techniques employed by these sites such as keeping the actual img src url in some attribute other than src swapping them when the placeholder is scrolled into view). the script just forces this to happen right away on page load and on DOM mutations rather than waiting for me to scroll.

Does the problem happen in Safe Mode? https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

yes, I've confirmed it happens in safe mode as well

(In reply to Negritas Sergiu from comment #5)

Hello! I have tried to reproduce the issue on MacOS 10.15 using 91.0a1(2021-07-12) but unfortunately I wasn't able to reproduce it.
Could you please answer the following questions in order to further investigate this issue?

1. Does this issue happen in the latest firefox nightly? Here is a link from were you can download it: https://www.mozilla.org/en-US/firefox/channel/desktop/

Yes, I confirmed the same behavior on the latest version of Nightly for macOS (91.0a1 (2021-07-12) (64-bit))

2. Does this issue happen with a new profile? Here is a link on how to create one: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Yes, I created a fresh profile on the same version of FF as I used in my original report (Developer's edition, 90.0b12 (64-bit)) and found the same flickering issue occured (not every time though, but most times I clicked on a bookmark)

3. Are you using any add-ons if so could you please list them?

I have 1 addon which is currently enabled and that is uBlock Origin v1.34.0.

I have 3 others that are installed but which are disabled and have been for many months now:

• Skip Netflix Intro which runs a content-script only on netlflix.com and has been disabled for a while.

• "Utility Belt" and "No Lazyload - Local" are addons which I've written myself and installed from file (not from the addon store). Both of them just run a couple of content-scripts on a variety of individual sites to change/add some functionality of those sites. None of these site are included in the bookmarks toolbar favicons from my example videos.

As stated above, I have found the flickering issue to occur in safe mode as well and so the addons don't seem likely to be related here.

Adding the QA-not-actionable since this issue can't be reproduce by the QA!

Thank you and have a nice day!

Is there anything else can I do or provide from my end to help troubleshoot this any further?

I realize it's difficult since it's not reproducible for anyone else besides myself but I would think the fact that I have been able to reproduce using a clean, new profile in my current install of FF as well as a completely fresh install of FF Nightly might be enough to narrow it down somewhat. As far as I know, this would rule anything related to add-ons or any profile-specific settings and

In reply to Marco Bonardo [:mak] from comment #6)

....
I quickly skimmed through the code but couldn't find a point where we'd update the icon if the icon is not updated. I could have certainly not noticed something that requires deeper debugging, but we should exclude any possible external cause completely first.

Marco, can you point me in the direction of where this source code lives? I don't have much experience with navigating FF's source code but I wouldn't mind taking a look myself just in case I happen to find something of note.

(In reply to danmattera1 from comment #9)

Marco, can you point me in the direction of where this source code lives? I don't have much experience with navigating FF's source code but I wouldn't mind taking a look myself just in case I happen to find something of note.

it's not so trivial, the code is a bit spread-around depending on the component. On the toolbar the notifications are handled by nodeIconChanged https://searchfox.org/mozilla-central/rev/4b88e0b8cca115009e82fdd65e5bf5812ff99128/browser/components/places/content/browserPlacesViews.js#523-538, but that notification is sent by a callback when the result (model of the view) receives a notification that the icon changed https://searchfox.org/mozilla-central/rev/4b88e0b8cca115009e82fdd65e5bf5812ff99128/toolkit/components/places/nsNavHistoryResult.cpp#4052-4060,4067,4082. The notification is sent by the favicons service when a favicon is updated in the database https://searchfox.org/mozilla-central/rev/4b88e0b8cca115009e82fdd65e5bf5812ff99128/toolkit/components/places/FaviconHelpers.cpp#1115,1143,1150 and https://searchfox.org/mozilla-central/rev/4b88e0b8cca115009e82fdd65e5bf5812ff99128/toolkit/components/places/FaviconHelpers.cpp#805
This requires to cross debug js and cpp.

I'm not sure how you could help without actually debugging it while it happens... I'd maybe try on a different system first if you can reproduce it, and check what may differ across those systems. IF you can reproduce on a different systems then you may have more effective Steps To Reproduce it for us.

Marking as P5 as we don't have steps to reproduce, which makes it hard to investigate.

This issue is the same issue as in bug #1360158, so I'm marking this bug, as duplicate of bug #1360158.