When does Mp3tag save its settings to disk?

When does Mp3tag save its own configuration settings? Are they saved immediately upon making a change, periodically written to disk, or only upon exitting the program? In other words, could a program crash prevent settings from being saved?

Case in point: http://forums.slimdevices.com/showthread.p...3592#post163592

Was this because Mp3tag only saves settings upon leaving the program, or did something else happen to undo the user's configuration changes? With obviously disastrous results.

As far as I can see, they are saved when closing the program. I just changed some settings and afterwards killed the process - upon restarting of Mp3tag, the new settings were lost.