The open file dialog is popped by Powerbox (aka. the the open and save panel service, a sandbox security technology) of macOS, not by Core Shell.
It's very likely an issue of Mac (or macOS), please first try rest the SMC of your Mac:
- For Mac with Apple Silicon, shut down your computer, wait 5 minutes, then power on the computer.
- For other Mac computers, see the Apple Support article How to reset the SMC of your Mac .
If the issue continues after SMC reset, then the "sandbox" folders of Core Shell may be corrupted, please take these steps to delete the Core Shell "sandbox" folders.
- Back up this folder:
~/Library/Containers/io.coressh.shell/, deleting the whole sandbox will cause it to be rebuilt automatically.
Restart the computer. Launch Core Shell and test. If the problem is resolved, you may have to recreate some of your Core Shell settings.
Quit Core Shell, and restore contents you previously backed up back to: