When editing a content class in a specific language, if we set the default item for an object relation attribute we will get a double slash in the URL, for some reason.

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

There shouldn't be two slashes after fre-FR.
Also, "language" is repeated. And the target translation is also added twice (fre-FR).