The Creation Date will automatically be set as soon as the Defect is created. Opened Date is automatically set once the Defect State is changed to Open; this will vary depending on if someone works on the Defect the day of creation, or if it is not picked up until a differnt day. If the Defect is Opened the same day it is created then you will see the same date for Creation and Opened. If the Defect State is changed back to a Submitted state at any point, then the Opened Date will go back to blank. Then once it is Opened again, the date will reflect that date. The Closed Date field works the same way as the Opened Date.