searchField doesn't work

[mastastealth]

I tried a simple version using selectize on Codepen and that works fine, but starting an ember project from scratch and then trying to replicate it doesn't.

The route:

export default Ember.Route.extend({
    model(params) {
        return {
            item: null,
            items: Ember.A([
                {
                    id: 1,
                    category: 'apple',
                    title: 'One' },
                {
                    id: 2,
                    category: 'application',
                    title: 'Two' },
                {
                    id: 3,
                    category: 'beta',
                    title: 'Three' },
                {
                    id: 4,
                    category: 'betap',
                    title: 'Four' }
            ])
        };
    }
});

the template:

{{ember-selectize
    content=model.items
    selection=model.item
    placeholder="Search for apple..."
    optionValuePath="content.id"
    optionLabelPath="content.title"
    searchField=["category","title"]
}}

Typing in a brings up a blank. I can only use the title, why is this?