Hi GlenJ , you're not able to split screens with AccountRight desktop. However, if you view your company file in the browser, you can have multiple tabs open at the same time (right-click an existing browser tab and choose Duplicate). So, you can have, say, your invoices open in one tab and your customer contacts in another (and have these on separate screens if you want).
I get how using the app on split screen monitors could amp up its versatility. Right now, AccountRight doesn't support that feature. You might want to suggest it on the Ideas Exchange Board for future updates.