1980835 - New-in-nightly tab title/site/metadata popup whips outside the window when tab list is scrolled

Status: UNCONFIRMED

(Firefox :: Tabbed Browser, defect, P3)

Description

[наб]

Attachment: Recording of the incident, whole display

Steps to reproduce:

Hovered over the first tab in the list and ctrl-shift-tabbed

Actual results:

The popup with the tab title/site/pid metadata whipped across half the display, well outside the window and well over the screen border

This is on current nightly (143.0a1 (2025-07-31) (64-bit) on Win32)

Expected results:

should've just gone away like it does in my old deved 87 or on esr 128

Comment 1

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

The Bugbug bot thinks this bug should belong to the 'Firefox for Android::General' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[наб]

Well it very clearly is since this is about desktop firefox

Comment 3

[Stephen Thompson [:sthompson]]

:jswinarton How likely is it that this was regressed by bug 1971233? I wouldn't have expected that to affect the tab hover preview. The tab hover preview refactor in bug 1971237 landed yesterday so that can't be a culprit. The reporter said it works as of 128 -- maybe DJ has ideas.

I'll put this on our team's board in any case.

Comment 4

[наб]

(ftr it works on 128 because 128 doesn't have the custom popup with the preview at all, since it still has what looks like a normal GTK hover thing with just text (which disappears instantly when disturbed))

Comment 5

[Ina Popescu, Desktop QA]

I tried to reproduce this in Nightly 145.0a1 on Windows 10 and Ubuntu 22.04, but did not observe the tab preview popup moving outside the window.
наб, are you still able to reproduce this issue in the latest Nightly? If so, could you provide any additional details to reproduce it (e.g. number of tabs or display setup)?

Comment 6

[наб]

Repro on today's nightly (145.0a1 (2025-10-06) (64-bit)). I'm on Windows 10. As you can see in the video, my display (in the X11 sense) is made up of two screens: 2560x1440 on the left and 1600x900 on the right. Firefox is in fullscreen on the small screen. Repro by making new tabs until you blow well past the screen width so there's scrolling, focus the leftmost tab, hover the leftmost tab, ctrl+shift+tab/ctrl+pgup to select the rightmost tab, the hover popup follows where the tab would be during the resulting scroll (=> intrudes on the left screen as the tabs scroll right). I can repro on a fresh profile HOWEVER it's much less visible because the hover popups for the tabs scrolling under the cursor quickly replace the original so it doesn't go as far outside the window bounds. Disabling image previews makes it much more visible under this test setup. (I have image previews on in my original configuration but I'm scrolling over mostly-unloaded tabs with no image preview so my setup behaves more like no-image-previews.)

Comment 7

[наб]

Attachment: repro with setup

Comment 8

[Ina Popescu, Desktop QA]

I don’t currently have a two-screen setup, so I’m not able to attempt reproducing this issue. Waiting for input from the developer since the component is already set.

Comment 9

[наб]

Attachment: single-screen repro

further investigation reveals this happens in windowed mode as well, and in both directions