I have noticed that when I first post something, either as a new discussion or as a response to someone else, I can edit what I just posted. When I come back quite some time later, the option to edit is not longer presented. I am wondering how long that Edit Article open remains available, or is there some set of conditions that would prevent modifying your posting?

Which explains why, 36 minutes after I posted the original question, that I am no longer offered the choice to Edit my original post.