Yahoo Chat Question How to tell when An IM was sent if there is no time or date on it?

[kathy p]

Last night I was online and as I went to sign out of chat I got a prompt saying "you have unread chat messages, do you still want to sign out?". I clicked on the message and it was an IM I didn't notice. What I want to know is, was this IM sent to me last night during that time I was signed on? It was undated and there was no time on it. I never got a prompt to read unread messages before last night so I am assuming it was but I was just wondering if that prompt means the message was sent last night. Thanks