Shoutbox

This is a feature of a script called Messenger Enhancer.  You can either change your preferences for the script (click on the script icon and then select message enhancer) or you can turn the script off completely (go into the Plus! preferences, click on the "Messenger" Tab up the top, then on the "Scripts" tab on the left and then un-tick the box next to "Messenger Enhancer" and click OK).