The diagnoses pool that is known and used by the Ref App (and in particular by EMR API) is controlled by two GPs: EmrApiConstants.GP_DIAGNOSIS_SET_OF_SETS and EmrApiConstants.EMR_CONCEPT_SOURCES_FOR_DIAGNOSIS_SEARCH.
On the other hand, when using HFE tags <encounterDiagnoses> and <encounterDiagnosesByObs>, there is an hardcoded "safeguard" that highlights for the user the fact that some of the diagnoses that are to choose from do have an ICD-10-WHO code. Example:
This underscores that by default ICD-10-WHO is the preferred coding system, since diagnoses that are ICD-10-WHO coded are highlighted to be spotted (and possibly preferably avoided) by the user.
The <encounterDiagnoses*/> tags should allow to specify the preferred coding system so that diagnoses that 1) are available but 2) are not coded in the preferred coding system are highlighted as such.
The tags should provide a way to specify the preferred coding system, something like this would be useful:
The concept source that is used to filter the diagnosis codes is hardcoded as being "ICD-10-WHO", see here.
Create a new attribute preferredCodingSource for the EncounterDiagnosesElement and EncounterDiagnosesByObsElement that will add an attribute to the field identified by #diagnosis-search in the encounterDiagnoses.gsp upon HTML substitution, eg.:
For backwards compatibility, if the conceptSource attribute doesn't exist or is empty then ICD-10-WHO will remain the default preferred coding source to filter with.