if selectDChecks is used with drule.get to get all the checks, in the result each 'dcheck' references 'drule', but it is an array :

"dchecks":[{"drules":[

{"druleid":"4"}

] ...

this does not match the documentation at https://www.zabbix.com/documentation/2.2/manual/api/reference/drule/get - and it is different from 1.8, whichi returns :

"dchecks":[{"druleid":"16" ...

not sure when this changed, but seems to be a regression