The AddBefore method attaches as the previous sibling the given NBElement and its children, or a copy of the given NBElement if it is still attached somewhere else.


- source (NBElement)
- The source element.

The before element.

An unattached element (an element with no parent), and any child elements it might possess, is connected to the element tree as the previous sibling of the target (this) element.
An attached element (an element that has a parent) is copied and the copy is connected to the element tree as the previous sibling of the target (this) element.