2026109 - Print renders all the <option> items in a <select> element instead of the selected one only

Status: VERIFIED FIXED

(Core :: Printing: Output, defect)

Description

[Denys [:denyshon]]

Attachment: select_element.html

In Firefox version 149, a regression has been introduced with the printing of HTML <select> elements. When printing, all <option> items inside a dropdown are displayed and included in the print output in addition to the selected one.

This behavior differs from Firefox 148, where only the selected option is rendered during print preview.

Steps to reproduce:

1. Create an HTML page with a <select> dropdown containing multiple <option> elements (a simple testcase attached).
2. Select one of the options.
3. Open print preview (Ctrl + P).

Actual results:
All options inside the <select> element are displayed and printed under the selected one.

Expected results:
Only the selected option is visible and printed.

Notes:
Reproduces in the release (v149) and the latest Nightly (v151). Does not reproduce in the previous release, v148.0.2.
Originally reported on SUMO: https://support.mozilla.org/questions/1572581

Comment 1

[Denys [:denyshon]]

[Tracking Requested - why for this release]:

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Printing: Output' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

Comment 4

[Kevin Locke]

I am affected by this as well and was able to bisect the regression:

Last good revision: f1c75460dbfd79bbb1bb34da66b8470993e41fd9
First bad revision: b967fdc6fff3b5ee0aa58fefd18df0f66f793b28
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=f1c75460dbfd79bbb1bb34da66b8470993e41fd9&tochange=b967fdc6fff3b5ee0aa58fefd18df0f66f793b28

It appears this was regressed by Bug 2011709.

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 2011709

:emilio, since you are the author of the regressor, bug 2011709, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 7

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2026109 - Improve cloning internal shadow trees for printing. r=smaug

Clone built-in stylesheets that aren't node associated: this fixes
select.css not applying which is what fixes the bug as reported.

Clone pseudo-element type (this fixes the dropmarker not showing up in
appearance: auto mode.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/5a7f14c9c40e
https://hg.mozilla.org/integration/autoland/rev/b484f520392a
Improve cloning internal shadow trees for printing. r=smaug

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/ae9a1488edb1
https://hg.mozilla.org/integration/autoland/rev/5047478e313f
Revert "Bug 2026109 - Improve cloning internal shadow trees for printing. r=smaug" for causing wpt failures @ select-combobox-print.html

Comment 10

[amarc]

Backed out for causing wpt failures

• Backout link
• Push with failures
• Failure Log

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/dbb958174858
https://hg.mozilla.org/integration/autoland/rev/4a9fdd30c2b6
Improve cloning internal shadow trees for printing. r=smaug

Comment 14

[Steffen Hofmann]

I confirm the behavior. Urgent fix needed

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/e4c240892131
https://hg.mozilla.org/integration/autoland/rev/e221b496d6d0
Fix windows fuzzy annotation.

Comment 16

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/58779 for changes under testing/web-platform/tests

Comment 18

[amarc]

https://hg.mozilla.org/mozilla-central/rev/4a9fdd30c2b6
https://hg.mozilla.org/mozilla-central/rev/e221b496d6d0

Comment 19

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 21

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2026109 - Improve cloning internal shadow trees for printing.

Clone built-in stylesheets that aren't node associated: this fixes
select.css not applying which is what fixes the bug as reported.

Clone pseudo-element type (this fixes the dropmarker not showing up in
appearance: auto mode.

Original Revision: https://phabricator.services.mozilla.com/D289935

Comment 22

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined/Reason for urgency: Multiple reports, simple fix.
• Code covered by automated testing?: yes
• Fix verified in Nightly?: yes
• Needs manual QE testing?: yes
• Steps to reproduce for manual QE testing: comment 0
• Risk associated with taking this patch: low
• Explanation of risk level: Trivial tweaks to the shadow root cloning. Note that uplift also needs this test-expectations only patch: : https://github.com/mozilla-firefox/firefox/commit/e4c240892131
• String changes made/needed?: none
• Is Android affected?: yes

Comment 23

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2026109 - Improve cloning internal shadow trees for printing.

Clone built-in stylesheets that aren't node associated: this fixes
select.css not applying which is what fixes the bug as reported.

Clone pseudo-element type (this fixes the dropmarker not showing up in
appearance: auto mode.

Original Revision: https://phabricator.services.mozilla.com/D289935

Comment 24

[Phabricator Automation]

firefox-release Uplift Approval Request

• User impact if declined/Reason for urgency: Multiple reports, simple fix.
• Code covered by automated testing?: yes
• Fix verified in Nightly?: yes
• Needs manual QE testing?: yes
• Steps to reproduce for manual QE testing: comment 0
• Risk associated with taking this patch: low
• Explanation of risk level: Trivial tweaks to the shadow root cloning. Note that uplift also needs this test-expectations only patch: : https://github.com/mozilla-firefox/firefox/commit/e4c240892131
• String changes made/needed?: none
• Is Android affected?: yes

Comment 27

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/cab52697e518
https://hg.mozilla.org/releases/mozilla-beta/rev/20f33569cebf
https://github.com/mozilla-firefox/firefox/commit/9c69aadc5ef1
https://hg.mozilla.org/releases/mozilla-beta/rev/a8b37887bec5

Comment 30

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Reproducible on a 2026-03-25 Firefox Nightly build on Windows 10.

Verified as fixed on Firefox Nightly 151.0a1 and Firefox 150.0b3 on Windows 10, Ubuntu 22, macOS 15.

Comment 34

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/f0a0ba8277f3
https://hg.mozilla.org/releases/mozilla-release/rev/f6446ed12ff6

Comment 35

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/9b0a19685111
https://hg.mozilla.org/releases/mozilla-release/rev/cf7430be6460

Comment 36

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Verified as fixed on Firefox 149.0.2 (treeherder build) on Windows 10, Ubuntu 22, macOS 13.