Default file manager

["Artur G. Sibagatullin" <ArtSib@uniqueics.com>]

Hi All! I'm using GNOME Desktop Environment. I was interested in
alternative file managers and tried to install Thunar file manager. I
don't know how but it became default file manager and when opening from
menu Places any location starts Thunar instead of Nautilus. When trying
to set up default application for the folder the field Open Folder could
not be selected and default is selected Open with Thunar. I removed
Thunar package but no result. This field is still present. How to remove
Thunar and make Nautilus open all Folders and Places?