Open all Music folders/Subfolders with Shortcut ?

Few years ago I used a shortcut able to open at once all folder and sub-folders in view list.

This time I need to open my Music Folder (~/Music/iTunes Media/Music)

For some unknown events (Power crash) my song list in iTunes is not complete anymore, too many have lost the link but still in the Music folder.

Fix them with iTunes one by one may take too long.

Under El Capitan I try again with Option/Click to open the last Music folder. It has open in a next column all songs folders but closed... and unfortunatly, those folders contain one or more others folders (album, songs titles).

Shortcut Option/Click to open all folders/sub-folders is what I remember, but it doesn't seems to be the right one.

Any idea what it could be ?