<select> should retain the initial value as the candidate (instead of showing...

<select> should retain the initial value as the candidate (instead of showing the empty select box until the values get filled in.)

This is useful in retaining the currnet value in case the candidates filling didn't work (for example, the other system we talk to is down.)

core/src/main/resources/lib/form/select.jelly

@@ -41,9 +41,14 @@ THE SOFTWARE.
   <f:prepareDatabinding/>
 
   ${descriptor.calcFillSettings(field,attrs)} <!-- this figures out the 'fillUrl' and 'fillDependsOn' attribute -->
+  <j:set var="value" value="${attrs.value ?: instance[attrs.field] ?: attrs.default}" />
   <m:select xmlns:m="jelly:hudson.util.jelly.MorphTagLibrary"
          class="setting-input ${attrs.checkUrl!=null?'validated':''} select ${attrs.clazz}"
          name="${attrs.name ?: '_.'+attrs.field}"
-         value="${attrs.value ?: instance[attrs.field] ?: attrs.default}"
-         ATTRIBUTES="${attrs}" EXCEPT="field clazz" />
+         value="${value}"
+         ATTRIBUTES="${attrs}" EXCEPT="field clazz">
+    <j:if test="${value!=null}">
+      <option value="${value}">${value}</option>
+    </j:if>
+  </m:select>
 </j:jelly>

war/src/main/webapp/scripts/hudson-behavior.js

@@ -1535,8 +1535,9 @@ function updateListBox(listBox,url,config) {
             originalOnSuccess(rsp);
     },
     config.onFailure = function(rsp) {
-        var l = $(listBox);
-        l.options[0] = null;
+        // deleting values can result in the data loss, so let's not do that
+//        var l = $(listBox);
+//        l.options[0] = null;
     }
 
     new Ajax.Request(url, config);