bug#1077: 23.0.60; x-create-frame: (wrong-type-argument number-or-marker-p nil)

[martin rudalics]

>> `menu-bar-lines'
>>      The number of lines to allocate at the top of the frame for a menu
>>      bar.  The default is 1.  A value of `nil' means don't display a
>>      menu bar.  *Note Menu Bar::.  (The X toolkit and GTK allow at most
>>      one menu bar line; they treat larger values as 1.)
>
>> so `nil' is a valid value and evaluating a menu bar item probably should
>> know how to handle it.
>
> I think the above doc only means that the C code interprets a nil as
> meaning  "no menu bar" when you set that frame parameter.  Whether it
> also means that this same C code can return nil when you query this
> parameter is not quite so clear.

I don't think it's of great importance.  From the example I gave earlier

(let ((frame (make-frame '((minibuffer . only)))))
  (frame-parameter frame 'menu-bar-lines))

the value returned by `frame-parameter' may have no relation to what is
actually displayed.

martin