Why some files open from source and others from the class files?

In one of my java packages I have some classes.  If I open class Foo.java from the Project view, then the source is opened in an editor.  If I select Foo.java and right click to get the Reveal In Finder menu item, then it shows the file in my source folder.  However if I open class Bar.java in the same package, then the Project view is scrolled down and updated to select the Bar class under a library root.  When I context click and select Reveal in Finder, the Bar.class file is shown.  In both instances an editor is shown but the randomness of it is driving me nuts.  How do I get IJ to open all classes from the source 1st?

This project was imported from Gradle if that makes a difference.