Ok by adding the loading indicator I noticed something is very wrong with this chatbox.. So I sniffed the network to see how many times it requests the chat messages..
I added 4 messages to the chatbox, and this is the sniffed network traffic during and after sending these 4 lines.
I have made the chatbox to refresh every 10 seconds, obviously something is wrong.
First thing that is probably wrong is that you do not reset the 10 second timer after I send a message (and thus refresh the chatbox). What else is causing this, I do not know.
Firefox btw, only 1 browser tab open.