This function works well in that it hides away the drop down lanes showing automation in the project window. However, it also folds (and hides the contents of) the standard “Group Tracks” folder if it contains a group track (with or without automation)
Create a normal folder track and place an audio track in there.
Record some automation on that track.
Create a group track, and leave it in it’s default folder (that is generated automatically by Nuendo).
Record some automation on the group track.
Select “hide all used automation” form the track folding sub-menu of the project menu.
The Groups Tracks folder will be closed (hiding both automation AND the audio track)
The normal folder track remains open.