I have had this idea for a while, the ability to add some context/background information whilst reporting messages via the chat. Sometimes it may be needed for you to add context and/or background information about, but not limited to, why something is offensive to you, why someone said something, etc.
Some ways for incorporating this could be, but not limited to:
Add a little box under the message (that is being reported) in the reporting messages menu.
Limit the number of characters allowed in this extra message to something.