When using responsive themes – either the default or blank theme, I can't select/change the submit button.
The button seems to be 'live' within FB. When I try to select it, I get a hand instead of a cursor then the form disappears when the button is clicked. I'm left with the generic submit button at the top-left of a blank area where the form was. I have to close FB and start again to get to my saved form.
I can't get a footer on the form either. Nothing happens when I click on footer (or submit button) in the elements panel.
I just discovered I can right-click the submit button to get to the properties. But within properties, there's no option to change the button color or substitute a custom button.
What is "regular: none.......+ -" supposed to do?

I can verify that this is definitely an issue, but somewhere along the line I could swear this issue with the disappearing form when clicking the submit button was fixed? Must not be. You're on the latest version right?

If you know which element you added last before it started you might want to delete it and re-add it.

Latest version.
It doesn't seem to matter what came last. Also, since I had this problem before, I started with the submit button first to see if it would be different.
I just tried a new blank form. I was able to select the button and there were options available I haven't seen before – including adding custom buttons. Added some things to the form (text field, comments...) – and I get the same problems as above. Even after deleting the other form fields, I can't get back to an editable button and footer.
Maybe I need to re-install FB?

Yup reinstall, You may need to go deeper and mess with the dot net files. I would open a support topic if the reinstall doesn't work because your not the only one to see this issue.

I'll give it a go after work today.
Maybe I'll get my responsive pop-up back