Hi,

WinCC Unified's screen-in-screen feature easily fulfills this requirement.

For the simplest solution, place two screen windows on your Start screen. Within these windows, display the screens you created at a size that matches the window size.

Each time you use the ChangeScreen system function, make sure you set the correct screen window path. Selecting "Current Screen" ensures that the screen change occurs within your start screen's window, rather than changing the main screen.

Kind regards
Stefan