Error highlighting in closed files

The problem is I have two JAVA  files in two different packages. One of them is Interface and the another one implemented it. I open the Interface class and change the abstract method's signature without refactoring. I save it and IDE does not show any errors (I expect the IDE to show me that the implementer class has issues). I have to open the implementer class in order to see the error. It seems there is no inspections for closed/unfocused files... 

 

I wonder if there is a way to enable something to trigger this error inspection. This feature is available in all other IDEs and without it, It makes this IDE unusable!

 

Thanks