I can tell you a half dozen work arounds, not sure if they'll work.
go to %appdata% and click out to the folder above it, then go to local and find shopsim, saved and look for the config with graphic options in it, change it back to windowed.ignore this - I'm wrong most of the configs are blank, and the settings in save game is likely too encrypted/clusterflubbed to warrant attempting to change it here.- Hit f11 - generally a shortcut for fullscreen/window in most games
- Hit alt-enter (windows based fullscreen shortcut, will attempt to override a window into fullscreen or back, if possible
- a third-party program that manages multiple displayers and borderless window/fullscreen optimization
- Delete the settings File previously mentioned (may cause harm to save game and other settings, not recommended.)
- Unplug/disable secondary, tertiary, and beyond monitors (via unplug or manually setting their functionality to "disabled" - there should be a couple places where you should be able to do this "hot"/plug n play - without having to restart to re-enable them.
- combine 2/4/6 - Once you have it so you can adjust the sittings, return it to windowed and then find one of the third party programs that lets you enforce a specific display's fullscreen (stretched window mode, boreless, acts near identical to fullscreen - likely also has option for mouse-bind and free (cursor stays in window frame or can freely exit to other display, or potentially there may be one that has a setting where you can hit a certain key to freely exit))
- To clarify - C -> users -> login name (potentially includes computer name) -> appdata -> local -> shop sim ->saved -> saved game -> settings : inside this file is words associated with resolution and window/fullscreen - but I also see a bunch of non-alphabet characters - implying its not being fully decrypted with notepad ++ - changing fullscreen to window and saving MAY work, but it may not, and saving it with the characters like that may result in an incorrect coding, and flubbernuck everything. - deleting it (and/or deleting the entirety of shopsim/saved folders) will reset (cause the game to create a new default) of the settings - but this may cause other things I don't realize, to also be reset.
- windows+r (opens run line) and %appdata% will bring your explorer to C-> users -> login name (potentially computer name) -> appdata -> roaming
- Must click back to Appdata and then go to local for this to serve as a shortcut to the location - Appdata is hidden by default in "login name/ PCN" and the average end-user will not naturally see this folder (Default folder option hides hidden folders, can be changed to show hidden folders)
- I didn't see the part originally about "turn off displays" if you're simply powering them off, my point still stands, if you're disabling them, fully, ignore my point about them.
- edit 2 - Hey also wanted to suggest when you do manage to return visual in game/window - try f11/alt-enter for enforcing fullscreen rather than the game's fullscreen option (leave the option as windowed, it will have to be fullscreened every time iirc) This may allow you to bypass the trigger that tries to call it to fullscreen for all displays, and only force it to fullscreen on the display it is current residing in.