Solution : https://service.sap.com/sap/support/notes/1399825 (SAP Service marketplace login required)
Key words :
topmost modal window, sap_basis support package, support packages refer, exact patch numbers, kernel patch, method get_screenshot, class cl_gui_frontend_services, frontend services, prerequisites sap, screenshot functionality
Related Notes :
1411440 | CL_GUI_FRONTEND_SERVICES: add screenshot functionality |
563161 | SAP GUI, SAP ITS & SAP IGS patches on Service Marketplace |