Strange callback behaviour

Hi all, Ok, I may just have screwed this up - but it looks pretty odd, so just in case: The file javaInstaller.php is at http://www.gornall.net/javaInstaller.txt rather than post it directly here - it's about 200 lines long. The crucial parts are pretty basic though - the callback is attached to the class function ok_cb() and gets called, sets $this->ok to 1, and calls Gtk::main_quit(). So far so good :-) The problem is that $this->ok is 0 when Gtk::main() exits! There are echo() statements in the class wherever $this->ok is set/reset, and none of them are unexpectedly called, so what's going on ? It's almost as though $this is wrong! I'm confused :-( Output looks like: C:\installer>.\php -q -c . install.php ok=0 (constructor, expected) Setting ok to 1 (callback, expected) Returning value of 0 (Huh!) 0 (from main code) ... with the relevant part of install.php looking like: $installer = new JavaInstaller($vm); $ok = $installer->createUI($status); echo $ok;