This addon is designed to give you a good idea where all those chat and system messages come from. It intercepts ANY message coming to the chatframes you specify and appends the last known value of "event". This should give you the event that generated that message.
/mess or /messevent
/mess show all Turns on event reporting for all chatframes (1-7)
/mess show 3 Turns on event reporting for ChatFrame3
/mess hide all Turns off event reporting for all chatframes (1-7)
/mess hide 3 Turns off event reporting for ChatFrame3
You can your settings by typing /mess report at any time.
Originally an addon by Cladhaire I noticed it was not on the SVN and deuced it and committed.
Feel free to add features from things like Iriels DevTools where you get a # in front of each line that you can click that also reports argument values to the events, etc.