colorscheme

I have a problem with making vim show a colorscheme fully (like in gvim). I've read about how to enable 256 color mode in terminal and it vim, but somehow it just doesn't work. The state of now is:

:echo &t_Co returns 256

Colortest shows all the colors:

But yet, vim doesn't show grey20 color of the colorscheme, instead using the terminal background. I also tried changing it to grey without success:

The system is ubuntu 14.04. and the terminal gnome terminal, although I've tried with terminator and tmux, with no success.

Any idea what could gone wrong?