From bogus@does.not.exist.com  Tue Jul 24 22:44:47 2007
From: bogus@does.not.exist.com ()
Date: Wed, 25 Jul 2007 02:44:47 -0000
Subject: No subject
Message-ID: <mailman.0.1185331487.10470.physionet-users@www.physionet.org>

    If wave opens with an empty signal window, this may mean that the X server's
    backing store is disabled. If possible, enable backing store and restart the
    X server. (Using XFree86 4.x, backing store can be enabled by inserting the
    line `Option "backingstore"' in the `Device' section(s) of the XF86Config-4
    file. If the X server is normally started by a display manager such as xdm,
    close all windows and restart the server with Control+Alt+Backspace.
    Otherwise, log out, log in, and restart the X server manually if necessary.)

You can check if backing store is enabled using the command:

    xdpyinfo | grep backing-store

which should produce output similar to:

      options:    backing-store YES, save-unders YES

Please write again if this doesn't solve your problem!

-- George