Arabic text not displayed Correctly with Xdataset

table definitions in firebird 3 database
  CREATE TABLE ACCOUNTS (
    ID                    INTEGER NOT NULL,
    CODE             VARCHAR(20) NOT NULL COLLATE UNICODE_CI_AI,
    NAME             VARCHAR(50) NOT NULL COLLATE UNICODE_CI_AI,
    FRGNNAME   VARCHAR(50) COLLATE UNICODE_CI_AI
);

In delphi client i have defined All the fields in the fields editor of the Xdataset as
    id               integer
    code          string    20
    name         string    50
    FrgName   string    50 

for Database Connection i use UniDac 7.1.4

All the data dispalyed correctly in the Grid except for the field Name show me the data as ''DE/J1 '  Instead of 'المدير العام' .
i test the same with sql server and there is no problem.
also i test it with Pure unidac  components wihtout TmsRemoteDB (uniConnection & UniQuery) and fireBird 3 and also there is no problem. 
when i delete the field definitions from the xdataset , the data displayed Correctly. 
i need to use the  Xdataset with All fields Defined and to be able to display all arabic text data Correctly.
Any Help?

thanks
Ahmed.

Update :

with sql database when define Name field as Varchar(50) i get the data correctly but when i define the field as nvarchar(50)  the problem appear.
i also check it with Elevatedb the same problem exist so i think it is Bug.
Any Comments?

Update  :

OKey My bad, i should define Name Field Datatype As WideString  Not string.
Solved.