ui.Application.getAppContainer() retrieves the MDI container name.
Syntax
ui.Application.GetCurrent().GetAppContainer()
Arguments
takes no input arguments
Usage and examples
...
DEFINE app ui.Application
LET app = ui.Application.GetCurrent()
CALL app.SetAppType("Child")
CALL app.SetAppContainer("cont1")
DISPLAY app.GetAppContainer()
...