Missing confirmation button

Hello,
as I needed a way for mass deleting of revisions, I tried VBO and I had to install the latest dev as deleting revisions of nodes did not work on current stable VBO.
However this is what I am experiencing.

1) I create a view based on revisions
2) I add the "Bulk operations: Content revision (VBO)" field
3) I select the "delete revision" action

When I go to my view and I try to select some items to delete and select execute, in the next page there is the list of selcted items, but there is no button to confirm the operation. So it is not possible to preceed.

Instead, if I configure the VBO field checking the option to skip confirmation step, the items are deleted