Você precisará recompilar a tela para poder editar essa opção. Você precisa manipular o sinalizador "MAXWIN".
I usually recompile screen to remove it. If you want to do it with packages, make sure you have the dpkg-dev package installed (you will need make etc. so also grab build-essential which may or may not be a dependancy on dpkg-dev) and use 'apt-get source screen' to grab the source for screen.
Extract the source (screen_4.0.3.orig.tar.gz). Make sure that you run the patch after the archive is extracted to create the debian package control files. Edit the config.h.in file and find this near the top:
:# define MAXWIN 40
Change the 40 to what ever limit you want.
Rebuild the package using dpkg-buildpackage and then install the .dpkg file over the top of your current screen installation. This will then set the window limit to what ever you defined earlier.
Isso explica como aumentar o limite, mas diminuir deve ser o mesmo. Boa sorte!