Solution : https://service.sap.com/sap/support/notes/1127038 (SAP Service marketplace login required)
Key words : 
multi agate instance environments, frontend services fails, exact patch number, fileopen dialog, dynpro execution, browser hangs, interim screen, 'enter' key, terms cl_gui_frontend_services, support packages
Related Notes : 
       
| 563161 | SAP GUI, SAP ITS & SAP IGS patches on Service Marketplace |