Adding Transaction in menu tab, but trx can not be seen under S_TCODE

Dear All,

I have one issue about transaction. I have added transaction(VD02) in menu tab in role. But, user who has this role can not run t-code. When I checked role, I saw that transaction does not exist under S_TCODE object in role.

Could you please help me what the reason of this issue is?

Thanks too much.