I'm not sure if this is what you're asking but it sounds so...you want stuff like chat (group, guild, ooc, etc.) to be in one window, and melee stuff (hits, spells, skills, crits, etc.) to be in a separate chat window, correct? If this is what you want, the default UI enables you to do all of that already, though it will take you a minute or two to get just right. You simply right-click the title bar at the top of that or any window to get a drop-down menu. In the chat windows under "Filters" you select almost every type of message that streams by and place it in the window of your choice, and you can make as many chat windows as you want by selecting "New chat window" in the menu.
I hope that helps, I apologize if I missed your point
