Written by gokcehan the 5 Sep 12 at 10:48.
Using byobu in a gnome-terminal, users are given a choice for creating a new tab from gnome-terminal or creating a new window from byobu. These two methods usually serves the same purpose (unless working with an ssh) and could be merged to avoid confusion.
First of all, I don't think you need to replace the old shortcut to implement the new one. The point is to add some convenient common desktop shortcuts (btw it's Ctrl+Shift+something, not Ctrl+Alt+something -- not that it's important) as well as the mouse support in order to get rid of the learning curve (think of it as terminal multiplexer for human beings =).
Also, I'm assuming you're not using byobu shortcuts (function keys) but only backend shortcuts (Ctrl+something, Ctrl+something). I don't see the point of using byobu instead of tmux if you're not using the shortcuts. Tmux supports all features of byobu and some more (mouse support etc.) and also is more mature and (imo) easily configurable than byobu.