The notifications are minimalist and display a picture of your friend who sent you the message, text message and even images (if attached to the message).
The Facebook Chat Pro also has the option to prevent your friends see you have viewed a message.
If you enable this option, when your friend sends you a message and you read, your friend will not know that you have already viewed the message.
After enabling this option, your friends will not know when you are typing a message.
Currently the Facebook Chat Pro is available exclusively for Google Chrome:Download
Please, after you install the Facebook Chat Pro, assess the extension in the Chrome Web Store: