Add a wizard to help with restoring files

[Nebucatnetzer]

For a lot of users it's not obvious that the "Mount" button is the one they should use to restore single files.
A little dialog which shows up after they clicked restore would probably help with that.
Something like: "Do you want to restore a single or just a few files or a complete archive?"
Depending on the answer they select it then either continues with the restore or with the mount function.