xshell for Telnet problem [1]

When I use Xshell to telnet from my Windows XP PC into a HP-UX UNIX system, I have noted that sometimes the letter 'q' gets inserted into the command line. it is not just a matter of a 'q' appearing on the command line, but rather the UNIX command shell, or whatever program I am running from the command shell reacts just as if I had typed the 'q'.

What is the cause of this mysterious 'q' ?

I do not have a LANG variable set in my environment.
The value of my TERM environment variable is vt100.
My font is 'Courier New'.
My font size is 9.

I experienced a similar problem and I remember that the problem has gone when the "Send Keey Alive" option was turned off. You can find the option in the Advanced tab of the session Properties dialog box.