# add the `* { box-sizing: border-box; }` to Front-End CSS file (that might break things)
# go to Front-End through Admin Console's `Content Mode` feature
# click on the `Section Properties` button to open the modal window
# take a screenshot of how window looks like
# go to that category editing through `Structure & Data` section
# take a screenshot of how window looks like
# confirm that modal window on both screenshots look the same (no issues, described in Confluence discussion are visible)