Conditions: v4.0.2 > v4.2, full version, inline editing. Firefox.
This button seems to insert a special nested div/span element, rather than -as most people would expect- a <br clear='all'> element. Worse, once the element has been inserted it is hard to remove.
Not sure what the usefulness/purpose of this feature is as webpages aren't generally designed for print anyway, but I'd like to replace the code it inserts with something more conventional such as a br or div with clear='all' attribute.
Problem is apparent on: ckeditor/samples/inlinebycode.html in distribution.