Category Permission Options are empty!

[Ninib83]

I was building a REST API with Umbraco and Dialogue for that i'm using Application Startup Class to inherits from IApplicationEeventHandler but in that case i cannot see the category permission option at the backoffice area. When i used UmbracoApplication as inheriance for the Application Startup class then it apears at the same time when ticked the permission option such as create topics which did not worked. the permissions dont take effect also API routing is not working because of inheriting from UmbracoAplication class. I have search every where to get help but unfortunately nothing found. Could you please help me with this issue as soon as possible? Thanks