1982519 - No default icon shown when an extension icon is missing

Status: RESOLVED INVALID

(Firefox :: Sidebar, defect, P2)

Description

[Ina Popescu, Desktop QA]

Found in

• Nightly 143.0a1

Affected versions

• Nightly 143.0a1
• Firefox 142.0b9

Tested platforms

• Affected platforms: All

Steps to reproduce

1. Install a sidebar extension that has no icon
2. Open the sidebar and observe the icon for that extension

Expected result

• A default extension icon should be displayed when no icon is missing.

Actual result

• No icon is shown.

Regression range

• N/A

Additional notes

• Please see videofor reference.

Comment 1

[Sarah Clements [:sclements]]

We'll use the same default icon we use for tabs, bookmarks, etc: "chrome://global/skin/icons/defaultFavicon.svg"

Comment 2

[EJiro Oghenekome]

Hi, can I work on this bug?

Comment 3

[Jackson Muturi Mwangi]

Hello I would like to work on this issue

Comment 4

[Betsy]

Hello, I would like to work on this.
Thanks

Comment 5

[Itoro James]

Hi,
I built Firefox locally and tested two scenarios:

1. A temporary extension with no icon defined in the manifest
2. A temporary extension with an icon path pointing to a nonexistent file

In both cases, I observed a fallback icon, the puzzle piece icon appearing correctly in
the sidebar, which suggests this bug may have already been addressed in the
current Nightly codebase without being formally documented or closed.

However, looking at the source code I noticed that line 263 in
sidebar-main.mjs sets:
newButton.iconSrc = newButtonValues.action.iconUrl;

This sets iconSrc directly without going through getImageUrl(), which already
contains fallback logic for missing extension icons. It is possible the fallback
is being handled elsewhere rather than at this level.

Could you confirm whether this bug has already been resolved, or if there are specific scenarios where the missing
icon issue still reproduces? I am happy to do more testing or work on a fix if
it is still needed.

Comment 6

[Itoro James]

(In reply to Itoro James from comment #5)

Hi,
I built Firefox locally and tested two scenarios:

1. A temporary extension with no icon defined in the manifest
2. A temporary extension with an icon path pointing to a nonexistent file

In both cases, I observed a fallback icon, the puzzle piece icon appearing correctly in
the sidebar, which suggests this bug may have already been addressed in the
current Nightly codebase without being formally documented or closed.

However, looking at the source code I noticed that line 263 in
sidebar-main.mjs sets:
newButton.iconSrc = newButtonValues.action.iconUrl;

This sets iconSrc directly without going through getImageUrl(), which already
contains fallback logic for missing extension icons. It is possible the fallback
is being handled elsewhere rather than at this level.

Could you confirm whether this bug has already been resolved, or if there are specific scenarios where the missing
icon issue still reproduces? I am happy to do more testing or work on a fix if
it is still needed.

Hi :nsharpley, Could you take
a look at my comment above when you get a chance?

Comment 7

[John Iweh]

Hi, im john can i be assigned to this bug?

Comment 8

[Kelly Cochrane [:kcochrane]]

Attachment: Screenshot 2026-03-23 at 12.51.16 PM.png

Here's a screenshot of the issue. They've added a new extension called "Tabs Sidebar", enabled it in the customize panel of the sidebar, and then hover over the button where it should be to show there's a missing icon for it.

Comment 9

[EJiro Oghenekome]

(In reply to Kelly Cochrane [:kcochrane] from comment #8)

Created attachment 9556873 [details]
Screenshot 2026-03-23 at 12.51.16 PM.png

Here's a screenshot of the issue. They've added a new extension called "Tabs Sidebar", enabled it in the customize panel of the sidebar, and then hover over the button where it should be to show there's a missing icon for it.

Okay, I think i can fix that after my first issue. Is that okay?

Comment 10

[John Iweh]

(In reply to Kelly Cochrane [:kcochrane] from comment #8)

Created attachment 9556873 [details]
Screenshot 2026-03-23 at 12.51.16 PM.png

Here's a screenshot of the issue. They've added a new extension called "Tabs Sidebar", enabled it in the customize panel of the sidebar, and then hover over the button where it should be to show there's a missing icon for it.

can i have this? i have not fixed any issue

Comment 11

[Kelly Cochrane [:kcochrane]]

(In reply to John Iweh from comment #10)

(In reply to Kelly Cochrane [:kcochrane] from comment #8)

Created attachment 9556873 [details]
Screenshot 2026-03-23 at 12.51.16 PM.png

Here's a screenshot of the issue. They've added a new extension called "Tabs Sidebar", enabled it in the customize panel of the sidebar, and then hover over the button where it should be to show there's a missing icon for it.

can i have this? i have not fixed any issue

3 people requested to fix this issue before you commented. Given EJiro Oghenekome already has some patches submitted, I'll check with Jackson next and then Betsy if Jackson doesn't respond. If neither of them respond within the next few days, I can assign to you. In the meantime, keep an eye out for new good first bugs we add to the Codetribute lists.

Comment 12

[Itoro James]

(In reply to Kelly Cochrane [:kcochrane] from comment #11)

(In reply to John Iweh from comment #10)

(In reply to Kelly Cochrane [:kcochrane] from comment #8)

Created attachment 9556873 [details]
Screenshot 2026-03-23 at 12.51.16 PM.png

Here's a screenshot of the issue. They've added a new extension called "Tabs Sidebar", enabled it in the customize panel of the sidebar, and then hover over the button where it should be to show there's a missing icon for it.

can i have this? i have not fixed any issue

3 people requested to fix this issue before you commented. Given EJiro Oghenekome already has some patches submitted, I'll check with Jackson next and then Betsy if Jackson doesn't respond. If neither of them respond within the next few days, I can assign to you. In the meantime, keep an eye out for new good first bugs we add to the Codetribute lists.

Hello Kelly, I responded on Element chat, i'd work on it.

Comment 13

[Itoro James]

Attachment: Bug 1982519 - Use fallback icon when an extension icon is missing r?nsharpley,kcochrane

Comment 14

[Itoro James]

Hello :kcochrane,

I have submitted a patch for this bug.

I found out that the iconUrl was
resolving to an empty.svg when
an extension has no icon defined. The fix updates
the iconUrl in getMenuIcon() in ext-sidebarAction.js
before it gets stored, and also updates
getEntrypointIconSrc() in sidebar-main.mjs and
getToolIconSrc() in sidebar-customize.mjs.

i added a test to browser_extensions_sidebar.js
to verify the fallback behaviour.

Patch: https://phabricator.services.mozilla.com/D289398

Comment 15

[Kelly Cochrane [:kcochrane]]

Alright since Jackson hasn't responded and Betsy is already assigned to other work, I'm going to assign this to Itoro

Comment 16

[Rob Wu [:robwu]]

(In reply to Sarah Clements [:sclements] | PTO until March 30th from comment #1)

We'll use the same default icon we use for tabs, bookmarks, etc: "chrome://global/skin/icons/defaultFavicon.svg"

Through all Firefox UI we default to the generic extension icon at chrome://mozapps/skin/extensions/extensionGeneric.svg

I would expect missing icons for extension buttons in the sidebar to also fall back to that generic icon. What is the reason for deviating from this default?

According to the report, the icon is blank/missing, and we should have something meaningful instead. The proposed patch does not only offer a fallback for the scenario in the bug, it goes beyond the request by also replacing the generic extension icon. Was this change also intended?

Needinfo Kelly/Nikki in case either of you know the answer since Sarah is on PTO.

Comment 17

[Rob Wu [:robwu]]

It looks like in the specific case of the extension, it is not that there is no icon defines, but that the extension-defined icon is literally an empty image. In https://phabricator.services.mozilla.com/D289398#10052138 I argued that if this is the case, that there is no bug in Firefox, and that we should close the bug, and inform the extension author of the issue.

Extension: https://addons.mozilla.org/en-US/firefox/addon/tab-sidebar-we/

Kelly, Nikki or Sarah: please let me know if my assessment of the bug's validity is accurate.

Comment 18

[Kelly Cochrane [:kcochrane]]

Yeah I'll let Nikki confirm as well but it sounds like this might actually just be an issue for the extension author rather than Firefox.

Comment 19

[Nikki Sharpley (:nikkis) (she/her)]

Thanks for clarifying Rob. I think, given your explanation, we can close this bug. Are you able to contact the extension author?

Comment 20

[Rob Wu [:robwu]]

I mailed the developer via the contact listed at their developer site linked from the extension listing at https://addons.mozilla.org/en-US/firefox/addon/tab-sidebar-we/