The PDF Preview of the primary file in the document should persist when you view individual files in the source (it would also be good if you could assign the build button to only the primary/main file so you don't have to switch to that file each time you make a change to a sub-file).
The PDF Preview of the primary file in the document should persist when you view individual files in the source (it would also be good if you could assign the build button to only the primary/main file so you don't have to switch to that file each time you make a change to a sub-file).