isLoaded observer does not fire at right time - ember.js

Question

I think I'm doing something wrong but I don't know what.
When my application loads it needs to retrieve all companies and when those arrive it needs to set a property activeCompany on my ApplicationController. But when I bind an observer on content.isLoaded on my CompaniesController is fires before the data is loaded.
Application
App = Ember.Application.create({
ApplicationController : Ember.Controller.extend({
needs: ['companies'],
activeCompany: null,
activateCompany: function(company) {
this.set('activeCompany',company);
}
})
});
Router
App.ApplicationRoute = Ember.Route.extend({
enableLogging : true,
setupController: function(controller, model) {
this.controllerFor('companies').set('content', App.Company.find());
}
});
CompaniesController
App.CompaniesController = Em.ArrayController.extend({
needs: ['application'],
activateCompany: function() {
console.log(this.get('content.length')); // 0
console.log(this.get('content.isLoaded')); // true
console.log(this.get('content.firstObject')); // undefined
this.get('controllers.application').activateCompany(this.get('content.firstObject'));
}.observes('content.isLoaded')
});
Why does content.isLoaded fire when my data is not loaded?
Maybe my concept is wrong but the rest of my application depends on the activeCompany to retrieve other data. I also have a 'company-switcher' which also sets the activeCompany property.
When I change my observer to content.#each it fires for all the items that are in the Array.
EDIT
I could work around it like this:
App.CompaniesController = Em.ArrayController.extend({
needs: ['application'],
activateCompany: function() {
if (this.get('content.length') > 0)
this.get('controllers.application').activateCompany(this.get('content.firstObject'));
}.observes('content.firstObject.isLoaded')
});
This only fires when my firstObject changes.

Answer 1

It turns out I should use findQuery. I tried it before like this: App.Store.findQuery(App.Company) but that didn't work. The right way of doing is like this:
this.controllerFor('companies').set('model', this.get('store').findQuery(App.Company));
I needed to get the store via this.get('store')