|Visio XML Reference|
Contains a work area for entering formulas in user-specific elements that are referred to by other elements and add-on tools.
Optional string. The name of the element.
Optional string. The universal name of the element.
Optional boolean. A flag indicating whether the element has been deleted locally. A value of 1 indicates that the element was deleted locally.
Optional int. The unique ID of the element within its parent element.
Like the Scratch element, the User element can be used by your solution in many different ways. The advantage of the User element is that the elements it contains can be named—elements in the Scratch element cannot be named.
If your solution has a well-defined purpose, it is suggested that you use elements that can be named and therefore provide clarity, such as those contained in the User element. Elements contained in the Scratch element are typically used to isolate repeated complex calculations.
The Name, NameU, and ID attributes of the User element are optional; however, at least one of the three must be present in a User element.
User-Defined Cells section