Native monitor support

Having native monitor support would be great.

Sheets handled it with 'screens' and redirects. A Screen would contain the UI layout, possibly like a PageContainer does now. You'd be able to mirror that screen's content to multiple terminal redirects, including monitors. The Application class would then filter monitor touches to the respective elements. You'd be able to have any number of Screens, so you could have different content on the computer screen and various monitors.