Solution : https://service.sap.com/sap/support/notes/1017458 (SAP Service marketplace login required)
Key words : 
sap_basis support package [, support packages refer, calendar controlstyle cnca_style_dtpicker [, date picker reason, date picker, abap constant], 620 patch 26its 640, /3 640 kernel patch 174, /3 700 kernel patch 100, note describes
Related Notes : 
       
| 1089968 | ITS Calendar: datepicker date not visible in navigator | 
| 796653 | |
| 563161 | SAP GUI, SAP ITS & SAP IGS patches on Service Marketplace |