Hi,
There’s an indicator to the right of a file’s name on the tab, a small white ball that appears instead of the ‘x’ button to close the file, to let you know if a file has been modified without being saved (i.e. it differs from the one on disk).
I have some open files on a directory which is mounted via SFTP, when I ummount this directory, all these files change to the white ball, which is correct because from Sublime’s pov the files are different now. Up until ST3, the moment I mounted back my directory, the indicator dissapeared, as everything was fine now and the version on sublime matched the one on the directory.
After I upgraded to ST4, this stopped happening. For whatever reason, ST4 feels it has a different file, or fails to detect that the file is there again. Restrting Sublime with those files open make no difference.