Ducati Scrambler 1100 Pro 2020 Owner's Manual page 212

If it is not possible to perform the desired
adjustment as explained above, it is possible to
modify the rear-view mirror position with respect to
the stem.
To do this, remove the rubber cap (1) by sliding it
downwards.
Unscrew the nut (2).
1
Fig 191
2
Fig 192
211