Checking items in and checking items out
When you open a Content Manager item from an external application using WebDAV, the item is checked out automatically, unless you explicitly choose, and are able, to open them in read-only mode.
If you external application lets you open an item in read-only mode, it often does so in the Open dialog:
When you save a Content Manager item back to the Content Manager using WebDAV, the item is checked in automatically.