When you start a drawing, Microsoft Office Visio creates a stencil that is specific to that drawing file, called the document stencil. Each time you drag a shape onto the drawing page, the shape's master is copied to the document stencil, and an instance (or copy) of the master is created on the drawing page. Instances inherit formatting and other properties from masters on the document stencil.
You can use the document stencil to do any of the following:
Keep track of which shapes you have used in your drawing.
Revise all instances of a shape on all pages in a drawing file by revising the master on the document stencil. For example, in an organization chart, to change the text color in all the Position shapes to blue, you can simply modify the Position master on the document stencil. All instances of the Position shape in the drawing inherit the changes.
Add shapes directly to the document stencil to make them easier to reuse. For example, if you have drawn your own shape and you want to use it in your current drawing only, you can drag it to the document stencil.
Open the document stencil
On the File menu, point to Shapes, and then click Show Document Stencil.
Note: You cannot save the document stencil to use in other drawings. It is only a component of the active drawing.