I've had this happen quite often on several different forums (including this forum). Someone asks a question and I post a solution. The OP doesn't acknowledge my post at all. Hours later, another poster comes along and posts a virtually identical solution (sometimes almost verbatim) and the OP comes back and tells the 2nd poster thanks for a great solution or whatever as if they never saw my post.
Why does this happen? Does it happen to others as well?