That was before I created this site, and I just assumed that tweaks/changes had been made to the FB since the last time I had used it, which was before that post. This most recent site is the first time I've used the pop-up menu.
I tested it on several devices and was relieved to see it worked fine on a friend's ipad as well as my client's iphone (since I have no Apple devices to test with).
Are we all in the Twilight Zone?
In the FB settings, it even has a percentage width and no height... that would seem to imply a non-static size.
I guess I'll have to do the skinny form idea for now and hope responsiveness returns to the pop-up option.
It seems odd that a responsive form option switches to fixed width when embedded in a responsive site. It seems CC would have a warning that a responsive template will no longer be responsive if the pop-up option is selected.