Unfortunately that doesn’t really fix it, just makes it slightly less bad.
This is maddening for me too! There must be some common-sense way to get around this?!
I have a page that’s 960px wide. A few elements (text box, buttons, input fields) in the middle. This is how it looks at responsive at 960px wide, the groups & text are now at the exact same width at which I created them in the UI builder:
But as soon as the responsive view gets a pixel narrower than 960x (my page width in the editor), all the elements on the page start to narrow – even though there is still plenty of space on either side:
Adding the empty-group-trick on either side makes the narrowing only slightly less bad, but it still happens straight away when the view gets smaller than 960px.