Flash's drawing tools let you create and modify vector shapes in your documents. There are two drawing models that give you a great deal of control when drawing shapes:
Merge Drawing model: This is the default drawing model, and automatically merges the shapes that you draw when you overlap them. For example, if you draw a square and draw or place a circle on top of it, and then select the circle and move it away, a "hole" is left in the square where the circle was placed.
Object Drawing model: Creates shapes as separate objects that do not merge together when overlaid. Each shape is a separate object that you can manipulate individually. When using the Object Drawing model, Flash surrounds a selected shape with a rectangular bounding box.
Flash's default model is the Merge Drawing model. To create shapes with the Object Drawing model, click the Object Drawing button in the Tools panel.
Tip: To merge shapes into a single, object-based shape, choose Modify > Combine Objects > Union.