This happens quite often, to the point of making this excellent editor practically useless. I cannot save a file because it says the file is in use by another process.
This occurred in version 2 or I upgraded to version 3 and it still happens. It happens even when evidently no other process is running that should interfere with the edited file.
How do I fix this. I have looked here for an answer and there seems to be one older post, but with no solution.