Both of the related records samples under the JavaScript API 2.0 samples site haven't been working for sometime. The related records query is not getting the required objectIds set by the previous selection. It is happening on line 103
relatedWellsQuery.objectIds = [features[0].attributes.OBJECTID];
features has the data but the alias is lowercase objectid. This leaves relatedWellsQuery.objectIds undefined so the related query can't be performed. There is now error callback so it just mysteriously stops.
