cmdtool and cursor-motion programs

[kranenbu at HLERUL5I.BITNET]

I have run into some strange behaviour of "cmdtool" in SunOS 3.5.

If manifested itself just after a "talk(1)" session where I left it to the
other party to shutdown the connection. In the mean time I had already
closed the cmdtool-window. When the connection was shutdown, the contents
of the window from before the talk-connection showed up in the icon. I
could just type in it and select and scroll text as if it were an open
cmdtool.  Opening it again (by clicking on the part of the icon image that
was still visible) produced a transparent frame which wasn't feeling very
well when re-siz ed or moved. Also, I could not type to it.

Here is how it can be reproduced (assume a cmdtool on pseudo-tty /dev/ttyp2):

Type (in another window):

   % echo "\E[>4l" > /dev/ttyp2

        (\E == escape, this the "ti"-capability from termcap)

Now you have a cmdtool that handles cursor-motion.  Close the cmdtool on
ttyp2.

   % echo "\E[>4h" > /dev/ttyp2  ("te" from termcap)

Now look at your shell prompt (or whatever) appear in your cmdtool icon.

It looks as if a part of cmdtool switches to the "open"-state on receipt
of "te" , and toggles back to "closed"-state when you "really" open the
tool by clicking on it with the mouse.

This can all be undone by sending the "ti"-string again to the *iconised*
cmdtool.

A similar effect can be obtained by sending "ti" to an iconised cmdtool,
then opening it, followed by a "te" to the open window. This also can be
reversed by sending "ti" to the open window, then closing it again and
sending "te" to the icon.

Is this a known phenomenon ?

P. Kranenburg
Dept. comp. sc.
U. of Leiden, The Netherlands.