1957434 - Dragging tab to the end of the tab strip briefly animates it from the original position when dropping

Status: VERIFIED FIXED

(Firefox :: Tabbed Browser, defect, P1)

Description

[Kestrel]

Attachment: Dragged tab momentarily flashes back to original position when dropped at end of strip

STR:

1. Drag a tab frome one end of the tab strip to the other.
2. Keep dragging so that it hits hard against the end of the strip.
3. Drop the tab.

Expected:
Tab remains in the final end position.

Actual:
Tab briefly returns to original position before animating to final end position.

Does not happen when dropping just before tab hits end of strip.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=653a7b21210b5b61a36af11b99ccd51e6c85a905&tochange=aa8a29bd1fb9668c81475b534b4ceb220dd4fe55

Regressed by Bug 1955112.

Comment 1

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

:dao, since you are the author of the regressor, bug 1955112, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Dão Gottwald [:dao]]

Attachment: Bug 1957434 - Remove workaround for bug 1954163. r?dwalker

I expect that bug 1955112 was really a duplicate of bug 1954163. Based on that, let's remove this workaround since it's causing trouble.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6ecfc5bd189e
Remove workaround for bug 1954163. r=dwalker,tabbrowser-reviewers

Comment 4

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/6ecfc5bd189e

Comment 5

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

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

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox138 to wontfix.

For more information, please visit BugBot documentation.

Comment 6

[Rares Doghi, Desktop QA]

Verified as fixed in our latest Nightly 139.0a1 (2025-04-08)

Comment 7

[Dão Gottwald [:dao]]

Attachment: Bug 1957434 - Remove workaround for bug 1954163. r=#release-managers

I expect that bug 1955112 was really a duplicate of bug 1954163. Based on that, let's remove this workaround since it's causing trouble.

Comment 8

[Phabricator Automation]

beta Uplift Approval Request

• User impact if declined: Please see https://bugzilla.mozilla.org/show_bug.cgi?id=1957434#c0
• Code covered by automated testing: no
• Fix verified in Nightly: yes
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: -
• Risk associated with taking this patch: low
• Explanation of risk level: we have no evidence that bug 1955112 was still an issue after bug 1954163 landed
• String changes made/needed: none
• Is Android affected?: no

Comment 9

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/1eb08d73bfea

Comment 10

[Rares Doghi, Desktop QA]

Verified as fixed in our latest Beta 138.0b5