Steps to reproduce
1. Folder owner UserX shares folder F1 with a group.
2. User1 is part of that group, so the folder F1 and its contents appear in User1's local file system.
3. User1 now accidently/intentionally deletes F1 from his local file system
I would expect the desktop client interprets this user action in some sensible way, for example "the user wants to stop syncing this shared folder" similar to what a user can do by unticking the shared folder in the desktop client's UI.
The folder F1 just disappears from the file system (ok) as well as from the desktop client's UI (??).
This leaves the user without any way to change his mind and start syncing this shared folder F1 again.
Moreover, if the user "undoes" the deletion (Ctrl-Z), the folder is recovered from Windows' trash bin and the desktop client considers this F1 folder and all of its contents as user private data instead of associating it back with the original shared folder.
Client version: 2.2.4
Client operating system: Windows 10 Pro
* Virtual Box appliance for Enterprise, downloaded on 2017-01-02.
* OwnCloud version: 9.1.3
* Accessing over http (no certificates put in place yet)
* No special configuration changes afaik.