In larger reviews, there are sometimes many chat windows. As the review progresses, sometime chats are "done", in that there is nothing more to discuss. These chats now polute the general chat space, and the "accepted" icon is removed if the author uploads another file (often causing the reviewer to look at old chats). Please add an ability to "close" a chat, where the "accepted" icon is kept on that chat line. Perhaps even the (sometimes long) chat bubble could be minimized once closed..