Re: Fix some tooltip related problems

[martin rudalics <rudalics@gmx.at>]

 > I thought that Emacs tooltips were Emacs frames.  What
 > prevents Emacs from doing what it wants in such a frame?
 > This works for me, for example:
 >
 > (x-show-tip (propertize "abc" 'face '(:foreground "gray")))
 >
 > What's different here from what you are talking about?
 >
 > OK, I'm using MS Windows.  But does this not work also
 > on GNU/Linux and Mac?
 >
 > And if that doesn't work on such platforms, can't we use
 > a ("normal") Emacs frame where such things do work?  Just
 > what is it that makes it impossible for Emacs to dim the
 > text in a tooltip?  Sorry, but this is not clear to me.

System tooltips are lightweight objects with restricted abilities.
They have uniform appearance and the single tooltip window is usually
shared among all running programs and the operating system.

Emacs tooltips are merely an emulation of system tooltips.  Most
restrictions of system tooltips have been retrofit artificially, like
uniform faces which are built into `tooltip-show' (but can be avoided
by using `x-show-tip' as you mention above) or the fact that only one
tooltip can be present at any time.

The great disadvantage of Emacs tooltips is that they are heavyweight
precisely due to their versatility.  Showing an Emacs tooltip here on
Windows with -Q incurs an entire GC cycle.  Also, there are some minor
annoyances like the one that showing Emacs tooltips for menu items
depends on the presence of a blinking cursor.

martin