Solution : https://service.sap.com/sap/support/notes/1523352 (SAP Service marketplace login required)
Key words : 
prerequisites program error- options dialog called, threadid=449137&tstart=0 downloading sap gui patches, /irj/sdn/sap-gui, symptom selecting proportional fonts, sap gui installation guide, options dialog called, sap gui session, terms sap gui, sap gui configuration, sap gui patches
Related Notes : 
       
| 1053737 | Expected release dates for SAP GUI for Windows & ITS Patches | 
| 563161 | SAP GUI, SAP ITS & SAP IGS patches on Service Marketplace | 
| 535308 | How to apply a SAP Front End patch? | 
| 330793 | Downloading patches |