how I created the sample

gistfile1.js

lwc:cv lchambers$ svn diff frameworks/rubric_manager_core/ apps/rubric_manager/
Index: frameworks/rubric_manager_core/views/manager/manager.js
===================================================================
--- frameworks/rubric_manager_core/views/manager/manager.js	(revision 9183)
+++ frameworks/rubric_manager_core/views/manager/manager.js	(working copy)
@@ -45,8 +45,38 @@
             
             hint: RubricManagerCore.RUBRIC_NAME_HINT
         }),
+        
+        
+        rubricActionsButtonView: SC.ButtonView.design({
+            classNames: ['header-button', 'button-list'],
+            layout: { top: 3, height: 30, left: 10, width: 30 },
+            action: function() {
+                SC.PickerPane.create({
+                  layout: { width: 300, height: 500 },
+                  contentView: SC.ScrollView.design({
+                      layout: { left: 10, right: 10, top: 10, bottom: 10},
+                      contentView: SC.SourceListView.extend({
 
-        rubricActionsButtonView: SC.PopupButtonView.design({
+                            contentBinding: 'RubricManagerCore.rubricTreeController.arrangedObjects',
+contentValueKey:'displayName'
+                            // exampleView: SC.ListItemView.extend({
+                            //       hasContentIcon: true,
+                            //       contentIconKey: 'icon',
+                            //       contentUnreadCountKey: 'count',
+                            //       contentValueKey: 'displayName'
+                            //     }),
+                            //     groupExampleView: SC.ListItemView.extend({
+                            //       contentValueKey: 'displayName'
+                            //     })
+                        })
+                      
+                  }) 
+                  }).popup(this, SC.PICKER_POINTER);
+                  
+            }
+        }),
+
+        _rubricActionsButtonView: SC.PopupButtonView.design({
             layout: { top: 3, height: 30, left: 10, width: 30 },
 /*            title: '_options'.loc(),*/
             classNames: ['header-button', 'button-list'],
@@ -66,6 +96,8 @@
                         { name: "_Rename this rubric".loc(), isEnabledBinding: 'RubricManagerCore.editingRubricController.isEditable', action: 'beginEditing', target: 'RubricManagerCore.rubricTitleView'},
                         { name: "_Delete this rubric".loc(), isEnabledBinding: 'RubricManagerCore.editingRubricController.isEditable', action: 'deleteCurrentRubric', target: 'RubricManagerCore.rubricListController' },
                         { name: "", isEnabled: YES, icon: null, separator: YES},
+                        { name: 'Common Core Rubrics', subMenu: [{ title: 'Submenu item 1' }, { title: 'Submenu item 2'}] },
+                        
                         { name: "_Rubrics".loc(), isEnabled: NO }
                     ];
                     
Index: apps/rubric_manager/controllers/rubric_manager_core_controllers.js
===================================================================
--- apps/rubric_manager/controllers/rubric_manager_core_controllers.js	(revision 9183)
+++ apps/rubric_manager/controllers/rubric_manager_core_controllers.js	(working copy)
@@ -12,4 +12,48 @@
 RubricManagerCore.rubricListController = RubricManagerCore.RubricListController.create();
 RubricManagerCore.userController = RubricManagerCore.UserController.create();
 RubricManagerCore.scalesController = RubricManagerCore.ScalesController.create();
-RubricManagerCore.importController = RubricManagerCore.ImportController.create();
\ No newline at end of file
+RubricManagerCore.importController = RubricManagerCore.ImportController.create();
+
+var fruit = "Apples Bananas Cherries Dates Eggfruit".w().map(function(name) {
+  return SC.Object.create({
+    displayName: name
+  });
+});
+  var userOwnedGroup = SC.Object.create(SC.TreeItemContent, {
+    displayName: 'Owned by Me',
+    treeItemChildren: fruit,
+    treeItemIsExpanded: NO
+    
+  });
+  var vegetables = "Arugula Beets Cucumbers Dandelions Endives".w().map(function(name) {
+    return SC.Object.create({
+      displayName: name
+    });
+  });
+    var sharedGroup = SC.Object.create(SC.TreeItemContent, {
+      displayName: 'Shared to Me',
+      treeItemChildren: vegetables,
+      treeItemIsExpanded: NO
+      
+    });
+    
+    var commonCoreGroup = SC.Object.create(SC.TreeItemContent, {
+      displayName: 'Common Core',
+      treeItemChildren: vegetables,
+      treeItemIsExpanded: NO
+    });
+
+var rContent =  SC.Object.create(SC.TreeItemContent, {
+  treeItemIsGrouped: YES,
+  treeItemIsExpanded: YES,
+  treeItemChildren: [userOwnedGroup, sharedGroup, commonCoreGroup]
+});
+
+RubricManagerCore.rubricTreeController = SC.TreeController.create({
+    
+    // itemsBinding: 'RubricManagerCore.rubricListController',
+    
+    content: rContent
+
+
+});