Hello! At least as of LyX 2.3.0 LyX displays a "Reload file" prompt, if it detects that the LyX file has been changed externally, e.g. by Dropbox, external version control, or user scripts. As a great bonus, LyX even checks if the contents (not only the modification time) has changed.
However, when changing a lot of files at once (e.g. checking out an earlier version of a document with many child-documents from Git), each file has a separate prompt, and even files that were previously opened only invisibly in the background are suddenly visible. The best work-around I could idemtify, was to close and restart LyX having enabled the setting *“Tools → Preferences → Look & Feel → Document Handling → Load opened files from last session”.* Is it possible to make LyX silently automatically reload the files, if no changes were made inside LyX since the last save? - Klaus
