Re: x-popup-menu - window object

[martin rudalics]

>  I guess I have a larger question:
>  When should one use 'list?

At the very moment, evaluating

'((50 50) (selected-window))

in buffer *scratch* gets me

((50 50) (selected-window))

while evaluating

(list '(50 50) (selected-window))

gets me

((50 50) #<window 42 on *scratch*>)

because in Elisp "cons evaluates its arguments" and `list' is based on
`cons'.

`x-popup-menu' expects, according to its doc-string, as first argument
something like "list ((XOFFSET YOFFSET) WINDOW)" where WINDOW denotes an
object of type window.  In practice, this means that you have to find a
function (like `selected-window') that returns a window object and feed
`x-popup-menu' with the _return value_ of that function.  It's not
sufficient to feed `x-popup-menu' just with the reference to a function
that would tell it how to find such a window.