Confusion between a form component's wicket:id and a PageParameter in Wicket 1.5.x

A Form has a strange behavior when a component has the same wicket:id than a page parameter.

To create a Bookmarkable link after a form is submited, setResponsePage is called, and a PageParameter object is given as a parameter :
PageParameters params = new PageParameters();
params.add("searchString", searchField.getValue());
setResponsePage(SomePage.class, params);

In Wicket 1.5, if "searchString" is also a form-component's wicket:id, the form will only be submitted once :
searchField.getValue() will always return the first value entered by the user.

Here's an example :

public class SearchPanel extends Panel {

public SearchPanel(String id)

{ super(id); add(new SearchForm("searchForm")); }

private class SearchForm extends Form<String> {

private static final long serialVersionUID = 1L;
private TextField<String> searchField;

public SearchForm(String id)

{ super(id); searchField = new TextField<String>("searchString", new Model<String>("")); add(searchField); }

@Override
public void onSubmit()

{ PageParameters params = new PageParameters(); params.add("searchString", searchField.getValue()); setResponsePage(ListContactsPage.class, params); }

}
}

I tested the same application with Wicket 1.4.17 and it was fine. I only had this problem in Wicket 1.5.2 and 1.5.3.