How to set text field non-editable in declarative syntax?

Which attribute do I have to add to the below text field definition in declarative syntax to prevent user input?
E.g.:
<v-text-field _id="name" caption="Name" width-full visible="true" />

readonly

Sorrily this doesn't work for me: the TextField remains editable even if programmatically setting fooTextField.setReadOnly(true).

What else did I miss to do? Testing the "book inventory" multi module example under Vaadin 7.6.2 with Valo theme and its accompanying scss. I'm able to deactivate its product filter TextField via filterIProbandList.setReadOnly(true). But the same doesn't work on the ProductForm TextField productName with caption "Product name".