Flash now comes with preset Workspaces that organize the screen automatically. Individual designers and developers like to customize the Flash screen by moving the panels and other screen elements to different positions. All of these Workspaces are customizable. If you would ever like to go back to the default layout for a Workspace, select Reset.
You may even save your own favorite layouts by selecting New Workspace.
Below are screen shots of some common Workspace layouts (Essentials, Designer, and Classic). Notice the Properties, Tools, Stage, and the Timeline are located in various places in each one.