I’m not saying it’s broken in all instances of the Dante theme. I’m saying it’s broken with my specific installation of the theme. It was working once, then sometime in the past few months, something changed and it no longer works.
And yes, I have tried it in Internet Explorer, Firefox, and Google Chrome. The behavior is exactly the same in all three browsers.
Another symptom of this issue is that on the second and all subsequent modifications of any content created with the swift page builder, such as a page or post, has extra line breaks added to the top and bottom of any text boxes.