A dgrid row disappears when sorting - dojo

Question

I've implemented the dgrid. It's really neat. However when I click on the row header to sort, all but one row disappears. I'm going nuts trying to figure out why....
Let's give this a go.
DGrid, it's a dojo based data grid, see http://dojofoundation.org/packages/dgrid/
When using this with Javascript and HTML and connecting to an Observable MemStore, the grid populates, with several rows quite happily displaying data. The columns are sortable, that is you can click on the the row/column heading. However - and here's the problem - when clicking on these row/column headers to sort the row's, all but one row disappears.
Using a Memory (dojo/store/Memory) a the dGrids data store work fine - ie the rows sort successfully. However when using the Observable (dojo/store/Observable) as a data store the sort causes the rows to collapse. Please see below examples.
Sort working great with Memory:
function populateGrid(Memory, message) {
var featureOne = {
"id": message[0].attributes["id"],
"Col2": message[0].attributes["Col2"],
"Col3": message[0].attributes["Col3"]
}
var featureTwo = {
"id": message[1].attributes["id"],
"Col2": message[1].attributes["Col2"],
"Col3": message[1].attributes["Col3"]
}
var data = [feature1, feature2];
var memStore = new Memory({ data: data });
window.queryRecordsGrid.set("store", memStore);
}
The error occurs when using Observable:
var memStore;
function populateGrid(Memory, message) {
var feature = {
"id": message[0].attributes["id"],
"Col2": message[0].attributes["Col2"],
"Col3": message[0].attributes["Col3"]
}
var data = [feature];
if (!window.memStore) {
window.memStore = new Observable(new Memory({ data: data }));
window.grid.set("store", window.memStore);
} else {
window.grid.store.notify(feature, feature.id);
}
}

Answer 1

This might or might not be your issue, but currently the items in your store don't have unique identifiers - or if they do, they're not being picked up by the store correctly. dojo/store/Memory defaults to assuming that store items each have a unique id. If you have another field which provides unique identifiers, you can make Memory aware of this by setting idProperty, e.g.:
new Observable(new Memory({ idProperty: "Col1", data: data }));
You also seem to be assuming that feature.id exists when you call notify but as far as I can tell from your code, it doesn't exist.