F1-F12 keys don't work without pressing Fn or stopped working at all
Make sure that the option Ignore system settings for F1-F12 is turned on. If not, enable it and restart Commander One.
When opening the app for the first time or after proceeding step 1 you will receive the following warning message:
Click Open System Preferences button.
In the invoked window click on the Lock icon in the lower-left corner and type the password.
Find Commander One.app from the list and put a tick in a checkbox next to it.
In case, if all of a sudden, F1-F12 keys stopped working, proceed with the following steps:
Go to System Preferences→Security & Privacy→Accessibility
Click on the Lock icon in the lower-left corner and type the password.
Find Commander One.app and remove it from this list by pressing "–".
Restart Commander One and proceed with the steps 1-5 above.