You can now use shift-return key combination to add a new line within a field when adding/editing items in your study lists.
Tip: In Headmagnet, the default behavior of the return button when editing items is to go to the next field or next item (if you are on the last field), since most users typically enter very short 1-line questions or answers for their items. This allows you to quickly add items without having to take your hands off the keyboard or press the tab key.