1960306 - Manage tab group panel moves when the sidebar is collapsed or expanded

Status: NEW

(Firefox :: Sidebar, defect, P2)

Description

[Alexandru Trif, Desktop Test Engineering [:atrif] [PTO 18-22]]

Attachment: tab_group_0.gif

Found in

• 138.0b6

Affected versions

• 139.0a1 (2025-04-13)
• 138.0b6

Tested platforms

• Affected platforms: Windows 10x64, macOS
• Unaffected platforms: Ubuntu 24

Preconditions

• sidebar enabled
• vertical tab enabled
• sidebar placed on the left side
• expand on hover enabled

Steps to reproduce

1. Create a tab group and right-click on the tab group button.
2. Hover over the tab group panel.
3. Hover over the sidebar launcher.

Expected result

• The tab group panel maintains its position.

Actual result

• The tab group panel moves left and right based on the sidebar state (expanded/ collapsed)

Regression range

• Not a regression.

Additional notes

• Attached a screen recording.

Comment 1

[Sarah Clements [:sclements]]

Stephen, what do you think about the priority of this bug? Does your team have capacity to take this on? If not, could you point us to the bit of code that would need updating?

Comment 2

[Stephen Thompson [:sthompson]]

:sclements The placement of the tab group context menu in vertical tabs came out of bug 1933547. The code is https://searchfox.org/mozilla-central/rev/56117379696ea0cffb94cd09c14cd022a8c5e4e8/browser/components/tabbrowser/content/tabgroup-menu.js#730-732 This gets passed to openPopup's options.position argument. The menu is anchored to the tab group's label container https://searchfox.org/mozilla-central/rev/56117379696ea0cffb94cd09c14cd022a8c5e4e8/browser/components/tabbrowser/content/tabgroup-menu.js#813 I'm not sure how the popup anchoring works, but I'd guess that the position of the anchor node is only getting updated once the collapse animation is finished?

Our team discussed this bug for a bit and there was some interest in placing the menu below (rather than to the side of) the tab group label in vertical mode. If we did that, the menu may not need to move at all when the side bar expands/collapses.

We aren't planning to prioritize fixing the animation in the near term, but :dao expressed interest in looking at this bug next week. We also wanted to ask :amylee about desired UX but she is on leave at the moment.

What is the rollout plan/rollout progress/current adoption for expand-on-hover?

Comment 3

[Dão Gottwald [:dao]]

After playing around with this, I think the best path forward may be to let the sidebar stay expanded while this panel is open. Same for the tab context menu, which currently feels a bit funky as well.

Comment 4

[Sarah Clements [:sclements]]

(In reply to Stephen Thompson [:sthompson] from comment #2)

What is the rollout plan/rollout progress/current adoption for expand-on-hover?

Thanks for all the information! Expand on hover is enabled by default as of 138 and we are rolling the new sidebar out to most users in 138, however it won't be the default visibility setting (no plans anytime soon to change that). So it does seem like it'd be good to fix in 139. Makes sense to have UX look at it first though.