bug#25511: 26.0.50; modify-frame-parameters modifies undesignated parameter?

[martin rudalics]

>> As a general rule: Never set a frame parameter right after creating a
>> new frame.
>
> Ok, I can modify some codes similar to it.

Try to avoid ‘modify-frame-parameters’ wherever it's possible.  There
might be still cases left where we have to use it because some frame
parameters cannot be processed on an invisible frame.  That's enough
trouble.

> In order not to hide the matte that includes the title bar, the
> menu bar, and the tool bar.  In reality on Cygwin, the form
>
> (make-frame '((left . 0) (top . 0)))
>
> doesn't work as expected; the new frame appears on the down
> screen and the position is erratic.

Can you try this with a native Windows build and compare the behaviors?

> The minimum values that
> display a new frame fully on the top-left corner of the upper
> screen is:
>
> (make-frame '((left . 0) (top . 1)))
>
> But frame-parameters shows left=8 and top=32 in that case.

What does a specification like

(make-frame '((left . (+ -8)) (top . (+ -32))))

give here?

martin