live windows

[Adam]

Hello,

I stumbled upon an interesting problem today. M-x emacs-version RET is
GNU Emacs 24.0.92.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.20.1) of
2011-12-22

I eval

(defvar a nil)
(setq a (selected-window))

in the *scratch*-Buffer.  Then I work a little bit (2 minutes or so)
without touching the window that displays the *scratch* buffer.  Then I
eval (window-live-p a) via M-: .  In some cases (I cannot figure out
what to do exactly), nil is returned, although I did not touch the
window.

Whats wrong?

Adam