Convert Object to Symbol
Flash CS4 Tutorial
How to Convert Flash Object to a Movie, Graphic or Button Symbol
A common way to create symbols is to start with an object, then convert it to a symbol. You can also start with a new empty symbol, add content to it, and then drag it to the stage. For information on the second method see topic, Insert New Symbol.
Add a rectangular object to the workspace with the Rectangle tool (r key).
With the rectangle selected, press F8 (Modify > Convert to Symbol).
In the dialog box, name your symbol and choose the symbol type (Movie clip, Button, or Graphic).
The dialog box also lets you set the symbol's registration point. The registration point is used as a pivot point in ActionScript when rotating and scaling. It is also used set the object's location on the stage.
Once you have created a symbol, double-click the symbol with the Selection tool (v key) to open the symbol timeline.
Symbols Conserve Resources
Look for ways to reuse symbols. It is much smarter to create several instances of the same symbol, then it is to build 20 variations of the same object.
Converting a Symbol to an Object
If you wish to convert your symbol back to an object, select the symbol and choose Modify > Break Apart (Cmd/b (PC - Ctrl/b).