Split to pages in the Whiteboard App. I see this as part of the 3-dot menu in the page viewer. Selecting this option from the page you are on, would allow you to select another page in the viewer. When selected, the first page where the option was chosen would appear to the right, and the page selected from the viewer would appear on the left. (Similar to opening a "new window" from the Chrome App. An enhancement to this would also be allowing one whiteboard file to be opened alongside of another whiteboard file.