Overflow CSS causing issues

In system.css there is the following bit of css

/* Avoid jumping around due to margins collapsing into collapsible fieldset border */
html.js fieldset.collapsible .fieldset-wrapper {
  overflow: auto;
}

This is causing weird side effects (shown in attached screenshot).

Despite the comment, I do not see any differences with or without this css, and because it is causing additional issues, I see no reason why it should not be removed. I would appreciate additional testing to make sure I am not missing any side-effects of removing this bit of code.