public class ToSplit {   
    // candidate method for extracting into super-class/interface
    // this method uses nested class in it's signature
    public ExtractClass extract() { return null; }    
    private static final class ExtractClass {}

    // method to keep in this class
    public KeepClass keep() { return null; }
    public static final class KeepClass {}
}

When I try to extract extract() method into  Interface/Superclass there is no way to move it together with nested ExtractClass which is required by method

Expected:
- checkboxes should be not only for functions, but for nested classes to be extracted as well
- when extract() method is processed and nested ExtractClass was not selected provide refactoring warning