Closed Bug 1644161 Opened 3 years ago Closed 3 years ago

Drop-downs with custom width resize on mouse movement


(Core :: DOM: UI Events & Focus Handling, defect, P3)

77 Branch





(Reporter: wbertrums, Unassigned)





(1 file)

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:77.0) Gecko/20100101 Firefox/77.0

Steps to reproduce:

I'm using Firefox 77.0-1 (with MOZ_USE_XINPUT2=1, MOZ_ENABLE_WAYLAND=1 and WebRender turned on) and Sway 1.4-2 on Debian Unstable.

  1. Click on a drop-down with a custom width.
  2. Move the mouse cursor.

Actual results:

See attached video.

Expected results:

The drop-down stays as wide, like in previous Firefox versions.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Component: Untriaged → Graphics: WebRender
Product: Firefox → Core

Wow, that looks pretty irritating. Thank you for reporting!

Re-categorizing so this can get the attention from the right folks.

Component: Graphics: WebRender → DOM: UI Events & Focus Handling

This only happens with Wayland, at least in Sway and GNOME Shell.

Dear reporter,
I can't reproduce the issue from my ubuntu platform. Perhaps the issue only happens in one of your settings or platform? Could you use a clean profile without all the settings and test it again? Thank you

Flags: needinfo?(wbertrums)
Severity: -- → S3
Priority: -- → P3

The same thing happens in a clean profile.

Flags: needinfo?(wbertrums)

I think this has been fixed on Nightly already, could you try a build from and test it?

Flags: needinfo?(wbertrums)

This still happens in Nightly.

I could even reproduce this in a new VM with Debian. All I've done in that VM is:

  1. Edit /etc/apt/sources.list to use unstable instead of buster.
  2. sudo apt update
  3. sudo apt full-upgrade
  4. sudo apt --purge autoremove
  5. sudo apt install gdm3 sway firefox
  6. sudo apt clean
  7. Edit /etc/environment to have MOZ_USE_XINPUT2=1 and MOZ_ENABLE_WAYLAND=1.
  8. Reboot.
  9. Open Firefox.
  10. Go to
Flags: needinfo?(wbertrums)

I ran mozregression and found bug 1640567.

Closed: 3 years ago
Resolution: --- → DUPLICATE
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