how to restrict delete option for an added element in projeqtor - by: prakash

I logged in as Tester role and attached few test cases for requirement
Then logged in as Developer role and navigated to this Requirement to update status.
There I am able to delete the attached test cases for the requirement which has attached by another person.

So tool is allowing to delete the attached/added elements for another users.
Note:- a) Developer role has assigned 'Updater' privilege to update the status of Requirements
b) all are assigned to same project.

Please advise me how to restrict 'delete' option for an added/attached element which has not added by own.

thanks in advance