Ok I eventually made it work.
I have to use a Model for *both* the provided values, AND the selected
object (sorry, I'm a Wicket newbie).
Thus, by adding a field to the page:
public CompanyConfiguration selectedCompany;
And then:
I got a /Unexpected RuntimeException Last cause: Attempt to set model object
on null model of component: form:companiesList/ whenever I select an item in
my DropDownChoice.
I read somewhere that it was because there is no Model set, but there *is*
one (a LoadableDetachableModel) :
