Frosinone Approach 122,600 MHz is not showing if you click anywere inside che CTR1 and CTR2, but only if you click directly over the airport.

The main Tower frequency is 119,350 MHz (now indicated as "Frosinone Tower Tower")
The other Tower/Approach frequency is 122,100 MHz, which is indicated as well as "Frosinone Tower Tower", it's a common general/backup frequency, used in a lot of mil or civ/mil airports here in Italy.

Unfortunately I don't have access to MILAIP, so you have to somehow trust what I say, which is based on real feedbacks from the ATC over there.

Regards.

Diego