[h-e-w] Overlays, font change on text change, and NTemacs

[C Y]

Hi all.  Some time back I attempted to write an improved Axiom mode for
Emacs.  While it works as expected on Linux (there is a somewhat boring
video here:  http://wiki.axiom-developer.org/axiomemacsswf.html) the
Windows version has one nagging problem.

It actually works pretty much as expected, except for a feature
involving turning input entries red when they are changed.  The idea is
any change to an entry will cause it to turn red, until it is evaluated
(this signals that the equation in the input box no longer corresponds
to the displayed result.)  On Linux, this works as expected - deleting,
inserting, what have you all turn the expression red.  On Windows,
however, inserting a new character into this overlay only turns the
inserted letter red - I have to delete something to have the whole
expression turn red.  (The exception is at the beginning - if I insert
a character at the beginning of the expression, everything turns red.)

Am I doing something wrong?  The code is here: 
http://wiki.axiom-developer.org/SandBoxAxiomEmacsMode/tangle?submit=tangle&chunk=*
The literate pdf of the code is here:
http://wiki.axiom-developer.org/images/SandBoxAxiomEmacsMode.pdf

Any help appreciated.  This is a bit frustrating because it is so close
to working the say way as the Linux version - I was hoping we could use
this instead of the raw terminal interface for the next round of
releasing, in order to have a bit more flexible environment.  However,
I wouldn't feel right about having this behaviorial quirk in there.  

Thanks much,
CY

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com