After an update of Debian v.10 it has happened to me that in the browsers, both Chrome, Firefox or Opera, I have lost the Spanish keyboard in the browsers but nevertheless in the OS it is correctly configured because I write in the terminal and I continue to maintain the accents and the eñe without problem.
I have searched in the configuration of the browsers and the Spanish keyboard option is checked but in no way.
I don't know if I'm missing another way to configure the keyboard that all browsers have in common.
Anyone else has happened?
Well, in the end my solution was to select the language, format and input source in English, save and then re-enter to select Spanish and Spain as seen in the image in all the options.
I don't know exactly what it could be but it served to reset the configuration in Spanish.
The same thing happened to me on another computer with the same Debian but I don't know if it had to do with the installation of a specific program, which was AnyDesk, but the latter is a hypothesis.
Same problem, but not even changing the language solved it. I uninstalled Anydesk and dependencies and on reboot it was back to normal.
sudo apt-get remove anydesk && sudo apt autoremove