Re: tooltip can be displayed outside the screen

[Juri Linkov]

> Your changes are good.  However, this text has another problem:
>
>     ! The offset is the distance between the X position of the mouse and
>     ! the left border of the tooltip frame.  It must be chosen so that the
>     ! tooltip window doesn't contain the mouse when it pops up.
>
> If you use a bad value, and the tooltip window does contain the
> mouse, what happens?

Since I am not the author of the last sentence, I don't know what it was
intended to warn against.  I tried to use a bad value on X, and the
resulted effect is the mouse pointer covering part of the tooltip window.
Also moving the mouse causes flickering of the tooltip window.  I have no
idea how to describe this behavior in the doc string.

BTW, on non-toolkit X builds using tooltips on menu items completely
garbles them.  Most likely this is caused by garbage collection, and
displaying tooltips makes GC to occur sooner than when tooltips are
disabled.

-- 
Juri Linkov
http://www.jurta.org/emacs/