In Multiplicity Pro, from the Seamless Display tab, you can configure your primary computer to use a display from a secondary computer, allowing you to extend your desktop area of that computer.
To configure Seamless Display remote connections, first check: “Allow this computer to accept incoming display shares.” (1)
(2) To add Seamless Displays, click the plus icon. The following prompt will appear for adding the connection:
(3) Once a connection is added, the pencil icon can be clicked to edit the currently selected computer’s Passcode:
(4) The trashcan icon can be clicked to delete/remove the currently selected saved connection information from this list.
Share my computer displays (Multiplicity Pro)
From the Secondary PC’s Multiplicity application,