The display list

Prior to AS 3, you could create a number of different types of visual objects in a Flash movie, including movie clips, graphics, buttons, text fields, bitmaps, components, and basic shapes. These objects weren't really organized in a hierarchical structure, and they all had very different ways of being created, destroyed, and manipulated. For instance, movie clips could be attached, duplicated, put on stage in the IDE, or created from scratch. Text fields could be created from scratch or created in the IDE. When you get into bitmaps, videos, components, and the rest, it seems like each type was created on a different planet and was shoved in to Flash and forced to work with the others.

The differences among these objects has been totally addressed in AS 3. Just about any type of object that you can see on stage is created from a class that extends the DisplayObject class. In other words, all of these objects are part of the same big family now, and they all behave the same basic way, in terms of how you create them, put them on stage, destroy them, and manipulate them on stage.