Normally a window that appears within an application containing a query or a message. It must be cancelled or replied to (answered) before it will disappear and allow you to continue.
“My Sales Engineer knows all his products. I can call and ask him anything and he's on top of it. Some other places just want to sell you something, but I've found Sweetwater to be a helpful, professional company to work with.” Steve Hockenberry, Berlin Heights, OH