When you have opened two playback screens, you can create composite outputs made from both videos.
The output will consist of the two videos pasted side by side, and will keep your synchronization settings.
The buttons for dual videos and dual image saving are located at the bottom right of the workspace, on the common controls bar.
To save a dual image, use the snapshot button of the common controls toolbar
To save a dual video, use the film button of the common controls toolbar
Note: The created image or video will have the drawings painted on.