Chat Tabs adds some features to the chat window that I thought would be useful.

Features:

Tabs:

The main feature of this mod. Chat tabs can be configured to use a regex filter to declutter your chat. Tabs can also be generated automatically when a player messages you.

Scroll Bar:

The chat scroll bar can now be clicked and dragged.

Chat Appearance:

The chat screen can be configured to use a different background color and can be extended to fit even more messages on screen.

Right Click:

Right clicking in the chat screen will open a menu that allows you to copy chat messages, edit the chat window, and add new tabs.