When editing a content class in a specific language, if we set the default item for an object relation attribute, the language is specified twice in the url.

The issue is very easy to reproduce.

Steps to reproduce:

1. From the administration interface access the following location: /class/edit/45/(language)/fre-FR
2. Add an object relation attribute to the class
3. Set the default selection item by clicking the "Select item" button, and select a content object

After selecting the content object the URL in the location bar will be:
/class/edit/45/language/fre-FR//(language)/fre-FR

The "language" is repeated. And the target translation is also added twice (fre-FR).