Oh, I found the problem.
Go to System -> Preferred Applications. On System tab the File Manager was set to EasyTag.
Have no idea how this come, but when I changed it back to "Open Folder" it obviously worked.
I guess it is a problem with Easytag debian package. It adds itself as a file manager for some reason. And because Easytag is alphabetically upper than "Open Folder" (caja
) it was selected by default.
I am on Debian Wheezy.
If someone can confirm this behaviour after installing EasyTag I could file a bug for it.