I know that the file will show up on whichever monitor has the majority of the file showing on it. I have 2 files, and I need to be able to specify which monitor each file is displayed on, but I don't see a way to specify a monitor, or to move the file in the window.
From what I can tell, the closest that I can come to my goal is that I can determine which document will show on the Primary monitor, and which one will show up on the Secondary monitor. I can then alert the user if both share the same monitor, and if they are on separate monitors, I can alert the user to which monitor will run which file.
The reason that I need to do this, is I need to replicate the 'Presenter Mode' feature of PowerPoint which allows the presenter to view speaker notes for a presentation while projecting only the presentation (don't ask - I have a coworker who hates PowerPoint, so they built a presentation for a client in Indesign so they could create a PDF presentation. I have been tasked to 'fix the problem' when the client asked how to show the speaker notes *facepalm*)
I have crerated a setup which has 2 copies of the same document, one which has an extra area with the notes and which controls the other one when a page is opened to keep them synchronized. The only part that I need to do to make this as user friendly as I need it is to be able to have the script choose which monitor will show the 'presentation' PDF, and which monitor will show the 'Notes page' PDF.