Created attachment 155680 [details]
Empty Refactored ClassA.java in preview

Link: http://services.netbeans.org/synergy/client/app/#/case/5149/suite/2030

Product Version: NetBeans IDE Dev (Build 201508240002)
Updates: Updates available
Java: 1.8.0_45; Java HotSpot(TM) 64-Bit Server VM 25.45-b02
Runtime: Java(TM) SE Runtime Environment 1.8.0_45-b14
System: Windows 7 version 6.1 running on amd64; Cp1252; en_IN (nb)
User directory: C:\Users\GOKUMAR\AppData\Roaming\NetBeans\dev
Cache directory: C:\Users\GOKUMAR\AppData\Local\NetBeans\Cache\dev

1. Open inner_to_outer.ClassA.java class
2. Put caret into ClassB body
3. From main menu select Refactor > Move inner to outer level...
4. Set Class Name: MyClass, check "Declare Field for the Current Outer Class" and type new Field name: myField
5. Press "Preview" 

Expected Preview in "Refactored ClassA.java" section:

package inner_to_outer;

public class ClassA {

    public interface MyInterface {

        public void m1();
    }
}

Actual Preview in "Refactored ClassA.java" section:

<complete empty>

I have also attached the snapshot of this.

If I click on "Do Refactor", refactoring actually functions correctly.