In direct contrast, if you edit any of the masters in the document stencil you will be offered the option to 'update all instances' derived from that master. You end up with shapes on the page that are linked to two different masters even though you started with only one and then edited it. If you subsequently make changes to the master in the original stencil and drag an instance onto the page, Visio creates a new copy of that master in the document stencil. In essence, the document stencil contains the working copy of each master that you've used at least once in a drawing. When you drag another instance of the same master into the drawing, Visio actually uses the copy in the document stencil to create the next shape instance. When you drag a master from a stencil onto the drawing page, Visio creates a copy of the master in the document stencil. Here’s what happens when you drag and drop in Visio. Consequently, many people aren’t aware that it even exists, let alone know of the critical role it plays when you want to change one master and have all instances inherit the changes. The mystery behind why changing the properties of a master does not update all of its derivative shapes lies in the existence of the document stencil, and is compounded by the fact that the document stencil is hidden by default whenever you start Visio.
