Hello. I am revisiting this because I really want it to work. Your code of:

$mainframe->registerEvent( 'onAfterContent', 'plgSqueeze' );
function plgSqueeze(){
sleep(5);

in the php file you provided here does not display the lightbox at all.

When I change this to:

$mainframe->registerEvent( 'onAfterDisplayContent', 'plgSqueeze' );
function plgSqueeze(){
sleep(5);

where onAfterDisplayContent is changed from onAfterContent, it does show the lightbox, but there is no delay. Is there any way I can get this to work? I know its a few months later but we'd really like to have some time delay in the popup. Thanks.