Jamie Zawinski's page (IIRC
, or maybe s/doc/docs/)
has some suggestions for improving the external widget code.
The correct URL is <http://www.jwz.org/doc/xemacs-wishlist.html>
assumes that at time of writing (in v. 19.14 or 20.2) it worked
reliably, which was not the case. The `bitrot' has just occured at
least in '96.