Use standards compliant RDF format. Bug 41225. r=pavlov

suite/common/sidebar/nsSidebar.js

@@ -99,13 +99,19 @@ function (aTitle, aContentURL, aCustomizeURL)
         throw Components.results.NS_ERROR_NOT_INITIALIZED;
     }
 
-    /* Create a "container" wrapper around the
-     * "urn:sidebar:current-panel-list" object. This makes it easier
-     * to manipulate the RDF:Seq correctly. */
-    var container = 
-        Components.classes[CONTAINER_PROGID].createInstance(nsIRDFContainer);
-    container.Init(this.datasource, this.rdf.GetResource(this.resource));
-    
+    // Create a "container" wrapper around the current panels to
+    // manipulate the RDF:Seq more easily.
+    var panel_list = this.datasource.GetTarget(this.rdf.GetResource(this.resource), this.rdf.GetResource(nsSidebar.prototype.nc+"panel-list"), true);
+    if (panel_list) {
+        panel_list.QueryInterface(Components.interfaces.nsIRDFResource);
+    } else {
+        // Datasource is busted. Start over.
+        debug("Sidebar datasource is busted\n");
+  }
+
+    var container = Components.classes[CONTAINER_PROGID].createInstance(nsIRDFContainer);
+    container.Init(this.datasource, panel_list);
+
     /* Create a resource for the new panel and add it to the list */
     var panel_resource = 
         this.rdf.GetResource("urn:sidebar:3rdparty-panel:" + aContentURL);