I guess you are referring to when you exit a CTR (Control Zone) and go uncontrolled without talking to anyone and squawking 7000 until you enter another CTR where you will be assigned a new code? Which is obviously normal since 7000 is non-discrete and cannot be used by ATC.
Sorry for not being clear enough. Europe loves controlling all aspects of life, and this includes airspace. The event of "going uncontrolled" is rare when flying the skies of Europe -- unless you fly ULM. I meant my squawk code is changed every time the new ATC (or their computer) believes my old code must be changed. There is not a pattern. Sometimes it happens when you leave the CTR and enter a D-level airspace, sometimes it happens when you move to a different FIR. Sometimes I keep the same squawk code for the entire flight. It is not a big deal: "oh, a message to reset the squawk code. 2543. Done."
My opinion is: flying as a pilot in FlightGear, I will be satisfied if the ATC manages locally the squawk code. If he sees a new aircraft with some code that doesn't collude with any other aircraft, don't change it. If for some reason or just for the fun of it the ATC believes my squawk code must be reset, then reset it.
Thing is I don't see why OpenRadar should include a handoff mechanism to pass the control of the aircrafts to another ATC. And I really don't see why we need a table airport/squawk codes. It is not wrong, of course. It is just I don't see the necessity of investing man-hours in this mechanism or this list.
Maybe it is just I don't have any experience as an ATC
