Bug#423014: console's last three lines become inaccessible once xdm start up

[Edward Welbourne <eddy@opera.com>]

Interestingly, when aptitude fires up the console-graphical package
configuration tool, during installation of new packages, it manages to
put the OK selector where I *can* see it, even though aptitude itself
fails to show me its last three lines.  (For example, when asking me
to hit return to continue, it does so where I can't see it; I have no
way to know whether it's showing that prompt or just taking a long
time to install some package that it's mentioned on a line I can't
see.)

	Eddy.