Messenger OnlyUnread (Hide Read Messages)

I use Facebook Messenger a LOT – and got pretty tired of unread messages disappearing because they sink to the very bottom. Facebook has no way to just show unread messages.

This extension hides messages that have been read in Facebook Messenger.

You click "Hide Read" and it starts hiding all the read messages, and refreshes the messages to fetch more.
Click "Pause Hiding" to pause the fetching, but still show the unread messages at the top.
And click "Show All" to go back to showing all the messages.