I am trying to create date properties that are automatically filled. I have a state property with 3 possibilities :"Started", "In Progress" and "Done". I would like to know at which time my task has been started, in progress and done. So far I can easily represent the date when the task was created ("Started") and the date the task was done ("Done" via last edited property). But I would like to know when my task was In progress. I have a formula that returns the now() date when the status is set to "In Progress". It's working perfectly BUT my problem is that the formula runs non-stop so the date changes every minute. What I would like to do is to fix this date value once it is filled. For example what I have in mind is : if property is empty and Status = In Progress set date to now(), if property is not empty then do nothing.
Do you know if there is a way to do that ?
Thank you very much !