bug#12971: 24.2.50; mouse-1 in info header lines tooltips

[martin rudalics]

> >   In mouse-drag-line don't exit tracking prematurely (Bug#12006).
> >
> >   * mouse.el (popup-menu): Fix doc-string and re-indent code.
> >   (mouse-drag-line): Don't exit tracking when a switch-frame or
> >   switch-window event occurs (Bug#12006).
>
> This change had a mistake: it needed to read the up-event even if the
> line is not draggable, so that the follow-link processing can take
> place.  Fixed in the emacs-24 branch.

Thanks for fixing this, martin