The Neighbors tool displays the markup of everything that is in contact with a certain piece. For example, the side door 1 of a counter display marking the basis of the joists, the bottom of the shelf, and hinges.
Example: 
The purpose of Neighbors function is to provide greater security at the time of registering holes also facilitate issues such as finding the height of the drilling of a shelf on the side. To use the function Neighbors, also called Contacts, follow the instructions below:
Plugin Editor, locate the Contacts button, highlighted in the following image:
When you click the Contacts button, the window below will be enabled:
View contacts the top face: displays marking the neighbors who are in contact with the upper face of the part upper face is the face that is visible in the Plugin Editor;
View contacts the lower face: displays marking the neighbors who are in contact with the underside of the piece lower face is not visible face in Plugin Editor;
Neighbors who are in contact with the upper face of the part will be represented by a continuous line. Imagine that the part shown below is a lower base:
Neighbors who are in contact with the part of the lower face will be represented by a dashed line. Imagine that the part shown below is an upper base:
