The chat window displays all the messages which players post into the room.
If you wish to read back through the chat recently posted to catch up on the conversation you can use the scroll bar on the chat window.
By default the scroll bar is locked so that whenever you send a message chat automatically scrolls to the bottom of the window and you see the most recent chat posted. If you wish to prevent the scroll bar from scrolling automatically simply click the to lock or unlock it.
If the text displayed in the chat room appears too large or too small for your comfort you can change its font size display. Use the button to control the font size of the chat text.