SUMMARY
Hello, I am using Arch Linux with KDE installed and I can't use any of my dead accent keys on qt applications.

 

I use a Portuguese (Portugal) keyboard, which contains a special cedilla key "ç" which works perfectly well. However the dead "´" and "~" keys dont do anything in kde applications.

The keyboard layout is correct because non qt applications (such as Chromium and Code) work perfectly well. This is clearly either a qt or a kde bug and not a keyboard problem. Though I'm not really sure if its a KDE bug because non KDE qt apps also suffer the same problem.


STEPS TO REPRODUCE
1. Press any accented dead key on any qt application
2. Press the second letter to accent

Example:
1. Key "´" + a

OBSERVED RESULT
Nothing happens

EXPECTED RESULT
The application should receive an accented character. The locales are all setup correctly though. All applications display accents correctly, they just don't accept them.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Arch Linux 5.4.13-arch1-1
(available in About System)
KDE Plasma Version: 5.17.5
KDE Frameworks Version: 5.66.0
Qt Version: 5.14.0

ADDITIONAL INFORMATION
I used xev on the Konsole and it detects the key perfectly, the program even correctly detects the character and knows that it's a dead key. On KDE settings, the keyboard is correctly setup as a Portuguese keyboard with dead keys. I know this is a recurrent bug, but all previous closed issues don't solve anything. Even the arch forums dont solve the problem.

I selected this as grave because it prevents me from using the system correctly. My language uses accents.