What functionality of the "Back"-button in a wizard UI is the best?
- Back button discards data from current page and navigates backwards.
- Back button keeps data (even if invalid) from current page and navigates backwards.
What functionality of the "Back"-button in a wizard UI is the best?
General answer is Back button shouldn't discard previously entered data. Holding the data avoids data entry duplication, if they returns back to this step. Data entry is quite painful activity for users.
Invalid data should be holded too (it provides recognition), still the system should verify critical data before switching to the next step.