Using help-at-pt and setting the delay to 0 does end up doing what I want,
thanks.  I agree that this is a globally useful feature, which is why I was
thinking of working to fix it at a lower level instead of just hacking
around the deficiencies.  Help-at-pt isn't the most elegant of solutions
either, but as long as it's part of emacs I suppose I'm fine with it.

On Thu, Sep 10, 2009 at 8:04 PM, Stefan Monnier <monnier@iro.umontreal.ca>wrote:

> > Essentially, I wanted to add echo-area messages to Flymake when the point
> > was in a section highlighted as an error.  js2-mode does this using text
> > properties when it defines overlays, which is another option I could look
> > at, but it seems much better to be able to just have an overlay for all
> of
> > this related information.  Flymake does use tooltips to display th error
> > message, but those seem to be only able to display when the mouse is over
> > the text, unless I'm missing something.
>
> This is a globally useful feature.  You might like to take a look at
> help-at-pt.el.  Notice that the feature you're trying to implement does
> not require hooking into the point-motion itself (like
> point-enter/point-leave/intangible properties) but only into the cursor
> movement (i.e. the position of point betwen commands).  This is an
> important difference, since one is implemented at a very low level and
> affects all kinds of unrelated operations, whereas the other is
> implemented at a very high level and interacts with very little
> other code.
>
>
>        Stefan
>
>