2026037 - Firefox fails to correctly enter predefined values into form, whereas Chromium does.

Status: RESOLVED FIXED

(Firefox :: PDF Viewer, defect, P1)

Description

[Mr Beedell, Roke Julian Lockhart [:B.RJL]]

Attachment: The Affected PDF File

The PDF File

Attach (recommended) or Link to PDF file here.

It is available at assets.publishing.service.gov.uk/media/68a4769b246cc964c53d29d8/MATCF_English.pdf, and attached.

How To Reproduce The Problem

1. Download the file:

   #!/usr/bin/env sh
   curl https://assets.publishing.service.gov.uk/media/68a4769b246cc964c53d29d8/MATCF_English.pdf#page=2:~:text=Example:%202023%20to%2024 -O -J
   xdg-open MATCF_English.pdf
   

2. Select one of the drop-downs on the second page:

   #!/usr/bin/env xdg-open
   location.hash = "page=2";
   document.querySelector('#pdfjs_internal_id_44R').click();
   

3. Select an exposed element of its context menu (shadow root):

   #!/usr/bin/env sh
   ydotool key 108:1 108:0 28:1 28:0
   

What The Expected Behaviour Is

Each square should be filled with the relevant data.

---

(add screenshot)

That depends upon id=278469. However, I'll attach it after submission.

What Went Wrong

The first two squares are filled with four squares' worth of data.

---

(add screenshot)

〃

Comment 1

[Mr Beedell, Roke Julian Lockhart [:B.RJL]]

Attachment: A Screencast That Demonstrates How Firefox Is Affected

My Environment

1. #!/usr/bin/env sh
   rpm -qf $(desktop=$(xdg-settings get default-web-browser); cmd=$(grep -h -m1 '^Exec=' /usr/share/applications/$desktop ~/.local/share/applications/$desktop 2>/dev/null | cut -d= -f2 | sed 's/ %.*//'); which "$cmd") \
   	--queryformat "$(
   		cat <<'EOF'
   Name: %{NAME}
   Version: %{VERSION}
   Release: %{RELEASE}
   Architecture: %{ARCH}
   Install Date: %{INSTALLTIME:date}
   Size: %{SIZE}
   Signature: %{SIGPGP:pgpsig}
   Source RPM: %{SOURCERPM}
   Build Date: %{BUILDTIME:date}
   Build Host: %{BUILDHOST}
   Packager: %{PACKAGER}
   Vendor: %{VENDOR}
   EOF
   	)"$'\n' | yq -P
   

2. Name: firefox-nightly
   Version: 151.0a1
   Release: 20260324002715
   Architecture: x86_64
   Install Date: Tue 24 Mar 2026 10:46:28 GMT
   Size: 382082898
   Signature: (none)
   Source RPM: firefox-nightly-151.0a1-20260324002715.src.rpm
   Build Date: Tue 24 Mar 2026 02:33:51 GMT
   Build Host: 811542a7f36c
   Packager: (none)
   Vendor: Mozilla
   

Comment 2

[Mr Beedell, Roke Julian Lockhart [:B.RJL]]

Attachment: A Screencast That Demonstrates How Chromium Is Unaffected

My Environment

1. #!/usr/bin/env sh
   rpm -qf $(command -v chromium-browser) \
   	--queryformat "$(
   		cat <<'EOF'
   Name: %{NAME}
   Version: %{VERSION}
   Release: %{RELEASE}
   Architecture: %{ARCH}
   Install Date: %{INSTALLTIME:date}
   Size: %{SIZE}
   Signature: %{SIGPGP:pgpsig}
   Source RPM: %{SOURCERPM}
   Build Date: %{BUILDTIME:date}
   Build Host: %{BUILDHOST}
   Packager: %{PACKAGER}
   Vendor: %{VENDOR}
   EOF
   	)"$'\n' | yq -P
   

2. Name: chromium
   Version: 146.0.7680.80
   Release: 1.fc43
   Architecture: x86_64
   Install Date: Wed 18 Mar 2026 11:43:33 GMT
   Size: 329340552
   Signature: (none)
   Source RPM: chromium-146.0.7680.80-1.fc43.src.rpm
   Build Date: Sun 15 Mar 2026 22:21:25 GMT
   Build Host: buildhw-x86-04.rdu3.fedoraproject.org
   Packager: Fedora Project
   Vendor: Fedora Project
   

Comment 3

[Calixte Denizet (:calixte)]

The white spaces are collapsed in the select options: they must be replaced by some &nbsp.

Comment 4

[BMO Github Automation]

Attachment: [mozilla/pdf.js] Use non-breakable spaces in options for the choice widget (bug 2026037) (#20977)

Comment 5

[BugBot [:suhaib / :marco]]

The patch landed in nightly and beta is affected.
:calixte, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
  • See https://wiki.mozilla.org/Release_Management/Requesting_an_Uplift for documentation on how to request an uplift.
• If no, please set status-firefox150 to wontfix.

For more information, please visit BugBot documentation.