I've been accidentally deleting pages due to new behaviour in Designer Pro X. If you delete an object by pressing the delete key or backspace key it seems to auto select the current page and pressing delete or backspace again will delete the current page, sometimes it gives a warning "Do you want to delete current page?" and other times it just deletes it without warning (more likely if you use backspace it seems). I didn't notice it happening at first and was scratching my head as to where all the work I had done had gone, luckily a couple of undos brought it back. I think DP7 handled this better ie. current page was not auto selected after deleting something.