Let’s say you are using Ubuntu (or some other Linux distribution) and an older version of Psychopy (the current version is 2022.1.4).
Psychopy 2022.1.4 does not have this issue. Thus, if that is an option to you, consider upgrading.
I’ve written a tutorial on how to install Psychopy 2022.1.4 in Ubuntu 22.04 using virtualenv that might help.
Nevertheless, if you choose to stay with the same Psychopy version (again, assuming that this is your case), you can modify the contents of the file paramCtrls.py (usually installed under home/user/.local/lib/python3.8/site-packages/psychopy/app/builder/dialogs/paramCtrls.py). The modification needed is described here.
If you are not familiarized with the notation used there: the signs indicate one line to delete (-) and two lines to insert (+), with one of them commented (# in the beginning of the line). Save the file and you are good to go 
Please, post here if you manage to solve the problem you’ve been having.
Best regards,
Flavio