swguy:
As the author of this plugin, I don't know. That's why I haven't answered any of your three prior requests for the same information.
You are welcome to experiment and try things out, but repeatedly asking the same question just annoys people and doesn't get you what you want. Why not try a new approach? For example, try digging in to MailChimp's documentation. They might have a way to handle this.
Here is how to get mailchimp to use a new window upon pressing "Subscribe".
add target="_blank" to line 13 of tpl_mailchimp_sidebox.php as illustrated in the code below
'method="post" target="_blank" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form">';
next step is to throw some javascript in to "size" the new window
then I will work on getting it to start in a lightbox
anybody care / want to help?