HI, I've had the same problem but was unable to find a solution. Has anyone else experienced this, it sounds like a bug?
I don't like posting bugs unless I'm sure it is a bug, I think the eZsys crew have thier hands full as it is, so I don't like to post every little problem I have as a bug. However if others have had this problem it may be worth posting.
I never got around to try to solve this problem but i found an extension that works perfectly.. it respectes parent node when browsing for related item.
extension found at: http://ez.no/community/contribs/datatypes/datatype_ezobjectrelationbrowse
