When I am in plain fish shell, a command is highlighted like so:
but when I am in
byobu-screen and type the same thing, I get:
When I do a
fish_config and look at my color palette, nothing is set to that darker blue color.
Note: I am on Mac OS X 10.9.1, and Byobu version 5.69 installed via Homebrew.
I think that's because screen by default on OSX is only 8 colors, while fish wants to use 256 (it's actually not related to byobu, which is why it works when you switch to tmux).
To get it to work, you'd need to recompile screen with 256 color support. You could do something like this:
git clone git://git.savannah.gnu.org/screen.git
sudo make install
cp screen /usr/local/bin/ # this should have precedence over the default screen in yr path
congrats on the engagement ;)