Bring address_states as is from spre_backend

app/assets/javascripts/admin/spree/orders/address_states.js

@@ -0,0 +1,27 @@
+var update_state = function(region) {
+  var country        = $('span#' + region + 'country .select2').select2('val');
+
+  var state_select   = $('span#' + region + 'state select.select2');
+  var state_input    = $('span#' + region + 'state input.state_name');
+
+  $.get(Spree.routes.states_search + "?country_id=" + country, function(data) {
+    var states = data["states"]
+    if (states.length > 0) {
+      state_select.html('');
+      var states_with_blank = [{name: '', id: ''}].concat(states);
+      $.each(states_with_blank, function(pos,state) {
+        var opt = $(document.createElement('option'))
+                  .attr('value', state.id)
+                  .html(state.name);
+        state_select.append(opt);
+      });
+      state_select.prop("disabled", false).show();
+      state_select.select2();
+      state_input.hide().prop("disabled", true);
+
+    } else {
+      state_input.prop("disabled", false).show();
+      state_select.select2('destroy').hide();
+    }
+  })
+};

app/views/spree/admin/orders/customer_details/_form.html.haml

@@ -25,4 +25,4 @@
     = button Spree.t('actions.update'), 'icon-refresh'
 
   - content_for :head do
-    = javascript_include_tag 'admin/address_states.js'
+    = javascript_include_tag 'admin/spree/orders/address_states.js'