So, Im not the only one who cannot stand the new steam chat update.
For sellers and traders its VERY slow and inefficient.
Here is how you revert back to the old UI.
https://steamcommunity.com/discussions/forum/1/1762481957306210604/
There are instructions on how to do it but if you do not want to click the link, keep reading.
Add this to the shortcut of steam. -nochatui -nofriendsui
“C:\Program Files (x86)\Steam\Steam.exe” -nochatui -nofriendsui
and then restart steam!
Enjoy.