firefox menu button stops working after update

[auquicu]

After an update of Ubuntu 18.04, firefox stopped working. Uninstalling and reinstalling does not help. Starting in safe-mode does not help.

The part that stopped working is certain menus. The seven menus on the menu bar (File/Edit/View/History/Bookmarks/Tools/Help) all work, that is, they show a drop-down menu for the left mouse button, nothing for the middle mouse button, and "Pin to Overflow Menu / Remove from Toolbar / Menu Bar / Bookmarks Toolbar / Customize" for the right mouse button. Fine.

The 3-bar button on the right gives zero reaction to left or middle button and comes with the same "Pin to Overflow Menu / Remove from Toolbar / Menu Bar / Bookmarks Toolbar / Customize" for the right mouse button. Bad.

The small triangles in menus as given in the preferences (for example to set Default Font or Font Size) do not react to any mouse button. Bad.

$ firefox --version
Mozilla Firefox 63.0.3
$ lsb_release -rd
Description: Ubuntu 18.04.1 LTS
Release: 18.04
$ apt-cache policy firefox
firefox:
  Installed: 63.0.3+build1-0ubuntu0.18.04.1
  Candidate: 63.0.3+build1-0ubuntu0.18.04.1
  Version table:
 *** 63.0.3+build1-0ubuntu0.18.04.1 500
        500 http://nl.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
        100 /var/lib/dpkg/status
     59.0.2+build1-0ubuntu1 500
        500 http://nl.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages

What I expected to happen: 3-bar and triangle mouse buttons react to left mouse button.
What happens: no reaction.

[Olivier Tilloy (osomon)]

What desktop environment / session do you use? I'm not seeing that in the default GNOME/X11 session on 18.04 (there's no menu bar there, either).

Can you please run the following command to attach additional information to the bug report?

    apport-collect 1804853

Thanks!

[Launchpad Janitor (janitor)]

[Expired for firefox (Ubuntu) because there has been no activity for 60 days.]