I am coding using Salesforce Apex and DocuSign API. Here a part of my code :
 

DocuSignAPI.Tab tab100 = new DocuSignAPI.Tab() ;                        
tab100.Type_x = 'Custom' ;     
tab100.RecipientID = 1 ;                           
tab100.DocumentID = 1 ;                           
tab100.PageNumber = 1 ;                           
tab100.XPosition = 40 ;                           
tab100.YPosition = 40 ;

Unfortunately, I try to use other field name like "Font, FontSize" but it is not recognized : I got this message "Variable does not exist : Font".

Thanks