plane icon. This make much more easier to go on an element from the multi relation_field
list (you don't need to go on the Jump Relation view to be able to select one
value).
The behaviour of editable multi relation fields (the most used in erp5) is not
changed.

Reviewed by romain.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@38054 20353a03-c40f-0410-a6d1-a30d3c3de9de