Closes issue #782.

common/content/commandline.js

@@ -1491,8 +1491,12 @@ var CommandLine = Module("commandline", {
                 this.wildIndex = this.wildtypes.length - 1;
 
             if (idx && idx[1] >= idx[0].items.length) {
+                if (!idx[0].incomplete)
+                    this.waiting = null;
+                else {
                     this.waiting = idx;
                     statusline.progress = _("completion.waitingForResults");
+                }
                 return;
             }
 

common/modules/dom.jsm

@@ -1567,12 +1567,15 @@ var DOM = Class("DOM", {
                     null
                 );
 
-                return Object.create(result, {
-                    __iterator__: {
-                        value: asIterator ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
+                let res = {
+                    __iterator__:
+                        asIterator ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
                                    : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); }
-                    }
-                });
+                };
+
+                for (let [k, v] in Iterator(result))
+                    res[k] = v;
+                return res;
             }
             catch (e) {
                 throw e.stack ? e : Error(e);