CGI.pm does not export the optgroup() sub unless you ask for it e.g. by 
use CGI qw/:standard/;

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so you must invoke optgroup() as a method i.e. 
$query->optgroup(...)

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just as you have done with popup_menu().

In reply to Re: CGI and optgroup menus has error by Arunbear
in thread CGI and optgroup menus has error by bradcathey

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