Assignment

Since upgrading to 1.8, we have lost the ability to change the type of assignment when selecting "Update This Assignment". Would like to change, for example, an assignment that had been an offline to an online text or upload single file option. None is visible, so we have had to create an entirely new assignment and eliminate the old one, just to get a new choice of the action the student is to take. Anyone else had this issue? Any ideas on what is going on? As we had had this ability in 1.6, it seems surprising to have less flexibility in the newer version!