Steps to replicate the issue (include links if applicable):
- In Firefox browser under un*x like operating system with X11/Xorg, start editing a Wikipedia page using an (non-visual) editor. (example sandbox link)
- Turn syntax highlighting on (right-most toolbar icon looking like a marker).
- Type a text (without a newline) with some characters typed using compose keys or so, e.g.
- character "å" (å typed as Compose a a )
- first … last (… typed as Compose . . )
- Müller (ü typed as ¨ u, or Compose u " )
- Turn syntax highlighting off again. Or, save the edit instead (plan B).
What happens?:
- Trailing text starting with a first character specially typed disappear, leaving only:
- character "
- first
- M
- If plan B was used, corrupted text was saved possibly without editor even being aware of it (see result diff of simpler test similar to middle example (a … b), like one captured in video below, but logged-in user session here.)
Other information (browser name/version, screenshots, etc.):
GNU/Linux or *BSD, Firefox browser (recent version, but the issue is many many months or years old), verified in:
- Arch linux, Xorg, Firefox 144.0
- (setxkbmap -layout us,cz -variant ,qwerty -option grp:switch, ⇧+AltGr compose key)
- OpenBSD 7.8, Firefox 144.0 (pkg_add firefox) (different machine; also re-cheched in libvirt / KVM virtual machine)
- (AltGr compose key enabled with setxkbmap -option compose:ralt)
- Debian 13 (trixie), Xfce desktop, Firefox 140.4.0esr
- (compose key enabled like above)
Always tested in new empty FF profile created (firefox -P).
Was not able to reproduce in
- Google Chrome
- Opera browser
- Windows 11, Edge browser and Firefox
- Debian 13 (trixie), GNOME (Wayland), Firefox esr; compose key enabled in settings
- Ubuntu 22.04 LTS (22.04.5), Firefox 144.0 (libvirt / KVM virtual machine)
- Ubuntu 24.04 LTS (24.04.3), Firefox 144.0 (libvirt / KVM virtual machine)
- Fedora 42 live CD
- current testwiki (looks different, "Syntax" label next to the icon)