As it seems, eZObjectRelationList does not considers the selected object when we search for existing objects using the search box.

Steps to reproduce:

1. Create a new "Custom Relations" content class from the administration backend
2. Add attributes "Text Line" and "Object Relations" to your content class
3. Set both attributes as required
4. Save your content class
5. Create a content object of type "Custom Relations"
6. Add a title to your "Text Line" attribute
7. In the "Object Relations" attribute, search for an existing object
8. Click on any existing object returned in the search results
9. Publish your content object

You should get the error "Missing objectrelation list input", as in the attached screenshot.