Once you manually input a purchase date for a security, you can not get rid of it - e.g. when you sell the security. You can change the date

, but can't clear it, and the date stays there whenever you re-add the security to a Watchlist in the future even if you don't have a position/quantity bought - doesn't really create a problem, just "inelegant" - I would think would be able to clear the field when it no longer applies