making error detection easier

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

@@ -1413,6 +1413,7 @@ function refreshPart(id,url) {
             new Ajax.Request(url, {
                 onSuccess: function(rsp) {
                     var hist = $(id);
+                    if (hist==null) console.log("There's no element that has ID of "+id)
                     var p = hist.up();
                     var next = hist.next();
                     p.removeChild(hist);