Extra distance above staff not applied when next staff up is hidden

1. Select staff properties of a lower staff, above which a staff is hidden in one or more systems due to 'Hide empty staves'.
2. Increase 'Extra distance above staff' and apply.
3. Note that the extra distance is applied if the staff above is visible, but not if the staff above is hidden.

Expected: Extra distance is applied regardless of the state of other staves.