Cant select attribute in reference selector

As described in the title. We are trying to get predefined warehouse locations to be selected in a edit reference selector. We use studio-pro 9.12.1. 
1 answers

Seems that you all, need so more training @avans ;-)

If you cannot select an attribute in the reference selector there can be multiple reasons

  1. Reference selector is editable, but no items available > no objects of the referenced entity available
    1. There aren't any objects
    2. You have a constraint on the selectable objects, resulting in an empty list
  2. Reference selector isn't editable
    1. The reference selector widget is set not editable
    2. The enclosing dataview or listview is set not editable (then ALL input widgets aren’t editable)
    3. The user doesn't have write access on the reference