martin rudalics <rudalics@gmx.at> writes:

>> Thanks. This frame parameter stuff is sooo over-engineered :-/.
>
> Don't ask me how much time I spent on it.  The most important thing
> would be to make values more characteristic - instead of 40 use 39 ...
>
>> Does it work with your changes, or is it still crashing?
>
> I found the crash when I tried to drag a child frame's child with the
> mouse.  So yes, it's crashing with my changes.
>
> martin

I've found the reason, please see the attached patch. If it works for
you, I'll put in master.

With your latest diff, and nothing additional on top of it, and with

(defun tty-3 ()
  (interactive)
  (setq tty-3
	(make-frame
	 `((parent-frame . ,tty-2)
	   (left . (- 10)) (top . 5)
                   ^^^^^^^

the placement of tty-3 seems wrong. Just saying, I think you mentioned
that you fixed that already.