Caps Lock and Special Characters (ÖÄÜ, etc.) Not Working on Chrome/Chromium (Swiss Layout)

[b4nds]

Describe the bug
I've encountered an issue where Caps Lock and certain special characters, such as Ö, Ä, Ü, and others, do not work correctly when using a Swiss keyboard layout. I’ve tested this on both Ubuntu and Xubuntu through Kasm Workspace in our cloud environment. This issue only occurs in Chrome and Chromium browsers, while Firefox on the same Linux machines works fine. Additionally, this does not happen on Windows Chrome. I've tried adjusting various settings and keyboard layouts without success.
Here’s a list of the affected characters:

Caps Lock:
Ö
Ä
Ü
¨¨
^^

Alt Gr +:
´´
~~
]]
}}

Shift +:
éé
``

To reproduce this issue, you can use the Kasm Workspace online by creating a Linux desktop demo and accessing Chrome.

System Description
Provide the output of:
cat /etc/os-release
uname -a

PRETTY_NAME="Ubuntu 22.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
Linux OSBoardOS 5.15.0-122-generic #132-Ubuntu SMP Thu Aug 29 13:45:52 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

KasmVNC Details
Provide the output of this command:
Xvnc -version

Xvnc KasmVNC 1.3.0.001ff1aa47cd6a2803c47c1b9ca572352681504a - built Feb 9 2024 18:50:26
Copyright (C) 1999-2018 KasmVNC Team and many others (see README.me)
See http://kasmweb.com/ for information on KasmVNC.
Underlying X server release 12008000, The X.Org Foundation

To Reproduce
Steps to reproduce the behavior (for non-installation issues):

Go to Chrome/Chromium on Kasm Workspace with a Linux desktop
Use Caps Lock and the special characters listed
Observe that these characters do not work as expected
Test the same in Firefox to confirm it works fine
Would recommend trying Capslock + öäü. The output should be ÖÄÜ but it comes out in small letters.

Expected behavior
Caps Lock and the special characters should work consistently in Chrome and Chromium, similar to how they work in Firefox.

Additional context
This issue seems related to how keyboard events are handled in Chromium. I found a forum post that explains similar problems with non-ASCII letters:

PS: Have fun. Handling of keyboard events for layouts which have keys for non-ASCII letters is utterly broken in Chromium and possibly also in Coherent ;)
Prepare to encounter double mapped KeyCodes (e.g., "_" and "-" both produce KeyCode 189 with Azerty but are physically different keys), key events which entirely lack KeyCode (like the ones on QWERTZ causing the SDL info), and more fun stuff.

This text was taken from a forum post I found here.

[mmcclaskey]

That seems odd that Firefox would behave different... can you confirm whether IME mode is enabled or disabled?

https://www.kasmweb.com/kasmvnc/docs/latest/clientside.html#ime-input-mode

[b4nds]

That seems odd that Firefox would behave different... can you confirm whether IME mode is enabled or disabled?

https://www.kasmweb.com/kasmvnc/docs/latest/clientside.html#ime-input-mode

It was disabled by default. I tried turning it on but it didn't change much.