Running Ubuntu 16.04, upgraded from 15.10.
I installed Dolphin alongside the existing Nautilus for testing purposes. Ever since, Nautilus is no longer showing open windows in the sidebar. The Files icon looks as if no window was opened and clicking it opens a new one. Typically it should show indicators for the number of open windows (up to three). Same problem for when I press ALT+TAB, the window icon is simply not there. Minimizing a Nautilus window therefore means that I lose it.
How can this be fixed?
I tried removing the icon from the unity sidebar, but then no icon appears when I open Files in the launcher.