[12:03 am: Futz Hackfest.]

Continuing with Building the Sign-up System...

One odd bit is when you drag a Popup onto the page and adjust the Width and Height, it disappears. Or rather, its visibility is turned off, though the eye indicator in the Elements tree doesn't reflect that:

‍

If you toggle it off, then toggle it on, the pop-up will appear:

‍

‍

I added a group within the Popup, changed the Width to 450 and Height to 220 so its edges would be equidistant from the Popup's, named it Group Container, and centered it horizontally and vertically:

‍