EL sequence sometimes leaves odd junk instead of erasing line

[GoogleCodeExporter]

What steps will reproduce the problem?

Occasionally, the EL sequence causes junk lines instead of erased blank lines 
to be displayed at its position. Specifically, every "blank" line contains the 
same junk, which is usually a line from scrollback.

I don't have an exact sequence to reproduce it because it happens rarely and 
unreliably, but I notice it always happens when switching between screen(1) 
windows into a mutt(1) window. At this point, all blank lines instead take 
content from a line recently scrolled off the top, usually a previous message 
line from my INBOX.

What version of the product are you using (you can see this by using Menu
-> About in the Host List)?

1.7.1

What type of system are you trying to connect to?

Linux/debian

If you are able to connect, what is the output of "echo $TERM", "uname -a",
and any other relevant information on the host?

TERM=xterm

Original issue reported on code.google.com by pev...@google.com on 11 Jun 2012 at 11:11