I ran the program DECCHECK.EXE.

Look here.

It show all decoders except one, as not preferred.

Should I do something for this?

mjolnarn:

As always, if it ain´t broke, don´t fix it...

Oh, I like this humor.

It only does not answer my question I had in mind: there is a button with which I can make another decoder preferred. Since a lot of Pinnacles decoders are listed, I was wondering why these are not prefered?

Or maybe ONLY one can be preferred?

I'm completely stupid in the knowledge of this.

That's why I never change something, just for trying. Trial and error results in my cases, always in Error.