Rectangle box with red or green bar

There is a little rectangular box next to the timer.  Sometimes it has a green bar in it.  Sometimes a full green bar, sometimes less than a full green bar.  Sometimes the bar goes red.  Sometimes it has a little red bar in the rectangle.  I am guessing it has something to do with the time you use on a move or in the game.  But I can't work it out.  Can anybody enlighten me as to the meaning of the colours and length of the bar in the rectangle.  

Thanks in advance.  Ozebloke

Hey, I believe this is how good your internet connection is. If it turns red, you (or your opponent if it is theirs) may be close to disconnecting and you may see a little warning. I have a friend who unfortunately has a terrible connection and his Bar is often red.

ping. low ping = good connection = green bar