problem with tty size in xterm

[Thomas.Wolff@siemens.com]

When an xterm is started that has about as many rows as fit on the screen,
it may get positioned so that its bottom is beyond the screen bottom.
In this case, the tty gets the wrong information about the window size.

For example, the following windows shortcut on a 1024x768 screen resolution:
D:\cygwin\usr\X11R6\bin\run.exe D:\cygwin\bin\xterm.exe -display localhost:0 -ls  -u8 -fn 10x20 -fw -misc-fixed-medium-r-normal-ko-20-200-75-75-c-200-iso10646-1 -geo 80x36
makes the tty pretend to have 35 rows.

With -geo 80x33 it works.

After a window resize, it also always works.

More symptoms:

Actually the problem does not seem to depend on screen vs. window size 
but rather on the actual initial position of the window:
Using the "working" setup (-geo 80x33) and starting a number of 
windows, which get positioned a little bit lower every time, the 
problem eventually shows up again

On the other hand, on a 1600x1200 screen resolution, the problem 
may also occurs, even if the window is fully visible.

Thomas Wolff