I modified the original plunker of
original documentacion ng-options
I am trying to assign in the "bogus" button the black object.
It is the same object but is not selected in the drop down with ng-model binding
{name:'black', shade:'dark'}
you can see in
Why the double binding is not working???
It's because it's not the same object, try using a filter to get your black item as in this plunker
$filter('filter')($scope.colors, {name : 'black'});
If you use a console.log of the $filter black item you'll see there is a $$hashKey: "object:3" value added to the item, that's why it doesn't take it as the same object.