To Access this dialog. Right click on a measure with volta brackets select Measure from the context menu and then "Edit Volta" from the sub menu OR right click on the volta brackets and then select "Edit Volta" OR double click on the volta brackets directly.

The variation numbers should be like 1 or 1, 3-5, 8. If the variation number is empty or just a single zero, the volta will be deleted.

Variation Number

Custom:

The variation on which to play these measures

Open ending

Select this to extend the volta range to the end of score/repeat or next volta.

Closed ending

Select this to define the volta range exactly covered by volta.