Change default "open with" for Documents directory

Solution 1:

If you have trouble opening any folder and therefor can not use "RightClick (Documents) > Open With Other Application... > File Browser" you can use this from command line

mimeopen -d ~/Downloads/

You will get a choice of options that are related to directories. Nautilus will be #1 in this list:

Please choose a default application for files of type inode/directory

    1) Open Folder  (nautilus-folder-handler)
    2) Other...

Make sure it says inode/directory and not inode/mount!

After choosing 1 all folders will be opened by Nautilus.

Ofcourse this list will have more options when you have more filemanagers have installed.

Solution 2:

RightClick (Documents) > Open With Other Application... > File Browser

http://ubuntuforums.org/showthread.php?t=1702576 << this may be helpful too