Turn off automatic 'read-only' conversion of Java to Scala

In my .java files, Intellij will show parts of the java code as scala code.    

... However, the code isn't actually changed; if I double-click on an area that's been visually converted, it will show the actual Java code.  So in the end, I have this half-java, half-scala code and it's unreadable and confusing. 

I have searched many times in vain to find what causes this.  Any 'how to turn this off' settings clues would be greatly appreciated!