We have a desktop application written in PyQt (let's call it OUR) that adds complementer functionality to an existing proprietary MS Windows application (named THEIR). THEIR runs fullscreen. We would like to switch to OUR and then back to THEIR programmatically when an external (hardware) event happens. Something like if we were to emulate the key combination ALT-TAB from OUR.
How can we switch to THEIR from OUR? How can we switch to OUR from THEIR on an event - for example when a timer times out?