Gergely,
I could not find a way to report this using Mantis so I am posting this here.
Symptom: Active airport/runway selector dialogue does not contain any data in the airport field.
Problem: The mechanism that retrieves this data appears to rely on a non-standard sector file.
Description: To troubleshoot the problem, I took our current sector file and removed all airports and runways except for one. The following results in the symptom:
[AIRPORT]
KJAX 118.300 N030.29.38.600 W081.41.16.300 C ; JACKSONVILLE INTL(AIRPORT)
[RUNWAY]
; KJAX - JACKSONVILLE INTL(AIRPORT