Thanks to Mihai Bazon and Bruno for the hints provided in
http://dynarch.com/mishoo/articles.epl?art_id=620
about "CSS-based separators".

The "New generation" patch is inspired by examples and suggestions
contributed by Shai Coleman <shai@eurotexte.fr>.
Many thanks, Shai.

Many thanks to Paul Adams <crazystick@users.sourceforge.net>
and Shai Coleman <shai@eurotexte.fr> for their suggestions about
the addition of the timeout feature to the Layers Menu.

Many thanks to Iacopo Spalletti <iacopo@spalletti.it>
for the key hint which is the basis of the 2.1.0 release
and has allowed to abandon the detection of the position
of the mouse pointer.

Many thanks to Tõivo Leedjärv <leedjarv@interest.ee>
for his key hint about an Object Oriented rewrite of the package.

Starting from version 1.1.0, PHP Layers Menu employs
the Template class of PHPLib; many thanks to the PHPLib developers.

The extended class, i.e. XLayersMenu, integrates code based on the
PHP TreeMenu 1.1 package, which is authored by Bjorge Dijkstra
<bjorge@gmx.net> and is placed in the public domain and published at
http://www.zinc.f2s.com/scriptorium/index.php/treemenu
Many thanks to Bjorge Dijkstra for his useful package.

Starting from version 1.0.4, the same idea behind KLayers
( http://www.kruglov.ru/klayers/ - Kruglov S.A. <info@kruglov.ru>)
is used in PHP Layers Menu; thanks to <us@planungsgruppeinternet.de>
who has pointed out to me the KLayers package.
Thanks to <us@planungsgruppeinternet.de>
also for other useful suggestions.

The code of PHP classes is commented according to the PHPDocumentor syntax
( http://phpdocu.sourceforge.net/ )
Many thanks to the PHPDocumentor developers.

Thanks to Patrick Erler <perler@yahoo.com>
for useful discussions about Opera 5.

Thanks to
Iacopo Spalletti <iacopo@spalletti.it>
Francesco Cipriani <f.cipriani@inwind.it>
Normando Marcolongo <normando@lugroma.org>
Jesus M. Castagnetto <jmcastagnetto@php.net>
Paulo R. Bagatini <arkanon@ceat.net>
Stephan Slabihoud <stephan@slabihoud.de>
Morten Poulsen <morten@poulsen.org>
Philipp Kamps <fipsfuchs@users.sourceforge.net>
Robert Gasch <rgasch@users.sourceforge.net>
Sasha Kushnirenko <kushnir@mx.ihep.su>
for useful discussions and suggestions.

Thanks to
Michele Conte <ceu@libero.it>
Tomas J. Fulopp <Tomi@uia.be> - <tomas.fulopp@skynet.be>
Hanno Saks <hanno@lv.parnu.ee>
Claudio Bandaloukas <rdfm@lugroma.org>
Danny Jovica <danny@e-pc.com.au>
Yves Mettier <ymettier@libertysurf.fr>
Jesus M. Castagnetto <jmcastagnetto@php.net>
Stepan Kadlec <steve@students.zcu.cz>
Morten Poulsen <morten@poulsen.org>
Sasha Kushnirenko <kushnir@mx.ihep.su>
for their bug reports.

Michele Antonecchia has prepared the logos and the shortcut icons.
Many thanks, Michele.

Many thanks to Comformatica/Vobis (Teramo), that has kindly allowed me
to use a MacOSX box to reproduce and fix bug 878361,
i.e. a rendering problem on Safari.
References:
http://sourceforge.net/tracker/index.php?func=detail&aid=878361&group_id=33447&atid=408327
http://sourceforge.net/tracker/index.php?func=detail&aid=878367&group_id=33447&atid=408329