I cannot delete and change text in all the input box

[giantroot]

I cannot delete and change text in all the input box (like "folder path", "user name", 'Filter exclude' et.al.).
I used many different method to install freefilesync on archlinux (yay and download .run install file). But all the versions get the problem. Anyone knows whats the problem. In windows its OK, but in archlinux, I cannot delete characters in the input box.
FYI. I user archlinux and fcitx5.

[giantroot]

Problem solved, because my locale LANG was zh_CN.UTF-8. Changed it to en_US.UTF-8 solved my problem.