I finally solved the problem with the navigation in Fences 3 under Windows 10.
1. Open the Windows File-Explorer
2. Select the "View"-Tab
3. Under Options -> Folder Options
4. Click Tab "View"
5. in "Advance settings" deactivate checkbox "Launch folder windows in a separate process"
im deutschen Datei-Explorer "Ordnerfenster in einem eigenen Prozess starten"
6. Press OK!
That's all.
Now when you click in Fences a Folder, the Folder opens "in" Fences
!!!
(Required "Allow navigation" is set in Fences-Window!)