Changes on disk
What the app does when a file open in a tab is changed by another program, a sync service or another computer.
A document open in Calmly Writer may change under it: you edit the same file on another computer and a sync service brings the new copy, or another program writes to it. The app watches the files it has open, on the desktop as they change and on Android by checking every few seconds, and tells you.
When you have no unsaved changes
The new version is simply there to take. The app asks: Load new version, which shows what is now on disk, or Keep current, which keeps what the tab shows and leaves the file alone until you save, at which point your version replaces the one on disk.
When you do have unsaved changes
Both versions matter now. The app asks whether to Reload and discard your edits and show the new file, or Keep my changes. Whatever you choose, nothing is lost: the version you did not pick is kept in Previous versions, labelled as the external change or as your replaced version.
When the file on disk is older
If the file on disk is older than the copy the app kept of it, for instance after a sync service rolled it back, the app says so before loading, and lets you choose between the file and the newer copy.
Sync services
Dropbox sometimes refuses to write a file while it is syncing it. The app waits and tries again, and in the meantime your changes are safe in the backup; a notice says so. With Google Drive on the desktop, save inside the Drive folder and let the Drive app do the rest. See Cloud folders.
More in Files
The files Calmly Writer opens and saves, what each one keeps, and which to choose as the default.
Saving by hand or letting the app do it, where new documents go, and how they are named.
The open dialog, the list of recent files, and the other ways a document can arrive in a tab.
The copies the app keeps of every open document, how to go back to an earlier one, and how to get back a document you closed without saving.
Word and PDF from the document on the screen, and what to use for HTML and Markdown instead.
Keeping documents in Google Drive, Dropbox or OneDrive, on the desktop and on Android, and what each service can and cannot do.
Calmly Writer