> For KEYBOARD USER it is nice to popped up at point.
> Howto, it is not nice for MOUSE USER.
We can easily check what kind of event was used to run the command and
then decide whether to popup near point or near the mouse.
Such distinction is already used to decide whether to use a dialog-ox or
the minibuffer to read a file-name.
> Emacs has many useful commands(mouse oriented commands) which are
> expected to be triggered from MOUSE. Some of them, including
> C-mouse-3, are not suitable for keyboard operatoin.
It's currently unsuitable, but we can make it suitable.
> I'd like to introduce `bring-mouse-to-point' for fill the gap.
> How do you think `bring-mouse-to-point'?
I think that moving the mouse is *evil*.
> I hope this is included to Emacs officially.
I'm not sure it's of wide appeal, but I don't expect users to write code
like the one you quoted, so there should be an easier way to do it.
E.g. a function which translates the window-relative coordinates of
a `posn' into frame- or display-relative coordinates.