ArcGIS JSAPI selectFeatures on feature layer with "stacked" features only returns one feature

Question

I am using the selectFeatures function to launch a popup when clicking on a feature. Because of the nature of my data, many of the features (street segments) have coincident geometry (they are stacked on top of each other). When I click on one of these segments that I know has multiple stacked features, the selectFeatures function only returns one feature (assuming the "top" one). If the features are adjacent (within my 10 pixel click buffer) but not coincident, it does return multiple features.

How can I have the selectFeatures return all features at that location, not just the one?

dojo.connect(map, "onClick", function (evt) {
    var query = new esri.tasks.Query();
    query.geometry = pointToExtent(map, evt.mapPoint, 10); //buffers click point by number of pixels(10)

    var deferred = featureLayerSeg.selectFeatures(query, esri.layers.FeatureLayer.SELECTION_NEW);
    deferred.addCallback(function (features) {
         console.log(features.length); //this returns 1 if the features are stacked on top of each other
    });
}

PS- I don't want to use IdentifyTask to a map service because these feature layers have already been filtered by the user based on search parameters.

Answer 1

I'm able to use featureLayer.selectFeatures() to get coincident features. My test is here: http://jsfiddle.net/xnNar/

The one thing I'd check is that your feature layer has a field with type esriFieldTypeOID and that your object IDs are unique.

The JSON for an object ID field looks like this:

{
  "name": "objectid",
  "type": "esriFieldTypeOID",
  "alias": "Object ID"
}