The Organize and Add Missing Usings refactoring allows you to quickly sort, remove unused and add missing using directives.
Supported: C#, VB.NET, Razor
To organize and add missing usings press Alt+Insert. From the pop-up menu, select Organize And Add Missing Usings. With that command JustCode removes unused usings, adds missing usings, and finally sorts all directives.
To organize and add missing usings you can also navigate on the main menu. Choose JustCode | Refactor | Organize And Add Missing Usings, or just press Ctrl+Shift+U