Currently, when I delete a file from Windows Explorer, Sublime Text doesn’t warn me that the file no longer exists. Instead, it merely acts like the file is unsaved, highlighting the close button (and turning the tab orange if you have that enabled).
As a result, I frequently move, rename, or delete a file in Windows Explorer, but continue working on the file in Sublime. When I save, I recreate the original file, with no sign at all that something is wrong. The file I want to edit is unchanged, but I instead have two different files under both names.
Another problem with this current behavior is that when I move or rename a file, the orange title bar provides no indication of whether or not I saved before renaming the file, so I no longer know if I have unsaved changes or not.
Notepad++ handles this situation better by telling the user that the file is no longer there, then asking in a dialog whether or not to close it. One potential flaw is that a careless user may accidentally click the “close” button when not intending to (this happened to me once).
Sublime should provide indication when the file is not on the disk, AND whether the file has been saved or not. This can be done using title bar colors or dialog boxes (like Notepad++). Preferably a notice box, but allow the user to close the tab themselves if they wish.
A related issue is when a file is updated on the filesystem. Sublime silently reloads the file on the disk without clearly informing the user. I’m not sure about the best solution, whether a dialog box would be too intrusive or prone to user error (clicking the wrong button).
EDIT: Under Menu -> [Preferences] -> [Settings - User], change