diff --git a/wcs/forms/root.py b/wcs/forms/root.py
index 0d34bb547..63d342146 100644
--- a/wcs/forms/root.py
+++ b/wcs/forms/root.py
@@ -383,6 +383,12 @@ class FormPage(Directory, FormTemplateMixin):
                     if not isinstance(v, str) and field.convert_value_to_str:
                         v = field.convert_value_to_str(v)
                     form.get_widget('f%s' % k).set_value(v)
+                    if field.type == 'item' and form.get_widget('f%s' % k).value != v:
+                        # mark field as invalid if the value was not accepted
+                        # (this is required by quixote>=3 as the value would
+                        # not be evaluated in the initial GET request of the
+                        # page).
+                        form.get_widget('f%s' % k).set_error(get_selection_error_text())
                     if verified:
                         form.get_widget('f%s' % k).readonly = 'readonly'
                         form.get_widget('f%s' % k).attrs['readonly'] = 'readonly'