@molovitch – Thanks for the great feedback.
@molovitch – That is more of an issue with the form than the plugin. Any forms made by our extensions will work perfectly well in a popup. Generally this is caused by the form not submitting via javascript/ajax. When normal forms submit they refresh the page, since your popup is likely closed on page load, this results in a not so great user experience.
I would recommend looking at one of the supported form plugins that do 100% work. They all are supported simply because they offer AJAX submission.
Hope that helps.
