The Organize and Add Missing Usings refactoring allows you to quickly sort, remove unused and add missing using directives.

Note
Language Support Supported: C#, VB.NET, Razor Not relevant: JavaScript, ASP.NET, XAML, HTML

To organize and add missing usings press Alt+Insert. From the pop-up menu, select Organize And Add Missing Usings. With that command Telerik® JustCode™ removes unused usings, adds missing usings, and finally sorts all directives.

Tip
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