I might not be getting how getExtUsers works, but if I use the following snippet:
[[!GetExtUsers?
&extUserRowTpl=`actContactgegevens`
&where=`{"User.id:=":"65"}`
]]
I only get results for users that have already filled in some information in the extra fields added with classExtender. For users that haven't, I get 'no users found'. (for example: I do get the results for user 65 but not for user 66, both exist, are active and not blocked).
What am I doing wrong here?