We would rather purchase it properly even though it’s GPL. We only use signed software because our production systems block unsigned software and our intrusion protection system checks the SHA256 hash against a cloud approved list.
We also want to support development of the software and we’d rather pay for somebody else to maintain it
I suggest removing those 5 options (Disable, 5 minutes, 15 minutes, 30 minutes, 60 minutes) and instead when the user clicks on Inactivity Sign Out a pop-up asks for the time in minutes. It would improve the interface and be much more customisable.
You could store the setting in XML and whenever the user clicks on Inactivity Sign Out it’d return the current setting.
This looks clean.