• Working with Items in a View

• Supporting Drag and Drop

• Supporting Object Persistence

• Working with a Pasteboard

• Sorting

• outlineView:acceptDrop:item:childIndex:

• outlineView:child:ofItem:

• outlineView:isItemExpandable:

• outlineView:itemForPersistentObject:

• outlineView:namesOfPromisedFilesDroppedAtDestination:forDraggedItems:

• outlineView:numberOfChildrenOfItem:

• outlineView:objectValueForTableColumn:byItem:

• outlineView:persistentObjectForItem:

• outlineView:setObjectValue:forTableColumn:byItem:

• outlineView:sortDescriptorsDidChange:

• outlineView:validateDrop:proposedItem:proposedChildIndex:

• outlineView:writeItems:toPasteboard: