use external_reference marker for force create subgadget

jsonform.gadget.js

@@ -251,6 +251,7 @@
       url,
       download_url,
       hash,
+      external_reference = false,
       queue;
     // XXX need use `id` property
     if (!schema_path) {
@@ -271,6 +272,7 @@
     hash = url.hash;
     url = url.href;
     if (download_url.startsWith("urn:jio:")) {
+      external_reference = true;
       queue = RSVP.Queue()
         .push(function () {
           return g.resolveExternalReference(download_url, schema_path, path);
@@ -329,6 +331,7 @@
       })
       .push(function (schema_arr) {
         checkAndMarkSoftCircular(g, schema_arr, schema_path, url);
+        schema_arr.external_reference = external_reference;
         return schema_arr;
       });
   }

jsonform/gadget_json_generated_form_child.js

@@ -1370,7 +1370,7 @@
             schema_arr = properties[key];
             filtered_schema_arr = schemaArrFilteredByDocument(schema_arr, json_document[key]);
             // XXX need schema merge with patternProperties passed key
-            if (checkSchemaArrOneChoise(schema_arr)) {
+            if (checkSchemaArrOneChoise(schema_arr) && !schema_arr.external_reference) {
               if (required.indexOf(key) >= 0) {
                 used_properties[key] = false;
                 q.push(render_field.bind(g, g, key, path,
@@ -1390,13 +1390,15 @@
               }
             }
             if (!used_properties.hasOwnProperty(key) &&
-                json_document.hasOwnProperty(key)) {
+                (json_document.hasOwnProperty(key) ||
+                 schema_arr.external_reference)) {
               used_properties[key] = "";
               q.push(
                 addSubForm.bind(g, {
                   gadget: g,
                   property_name: key,
                   parent_path: path,
+                  delete_button: !schema_arr.external_reference,
                   schema_arr: filtered_schema_arr,
                   json_document: json_document[key]
                 })