Usually if you type and send (or copy and paste some text) some long message it will show normally while wrapping to the borders of the current chat window size. But if the line of text (usually URL links) has no spaces and is longer than the current chat windows size it won't wrap and go beyond the border. All subsequent normal long messages will not wrap also and will go to the not seen border set by the long "no gap" message or link before. This will continue until "no gap" message or link move away from the current history in the chat window. Spark should break links into multiple lines and wrap them too.