Since the latest version update there is a small bug in the date field(s) in the 'new item' panel.
When I type in the date directly (so not clicking in the calendar), after typing in day, month, when I reach the year, the day and month disappear again.
I use this method a lot when transferring older items from my old blog to the new one.
Workaround: temporarely write the date in the text field and cut/paste it into the date field(s), e.g. 08032008.
I use version 2.2.3 of PivotX
Working with Firefox 3.6.6