This prevents windows in user supplied text and html content. It will isolate text collections across DOMText nodes and inline/inline-block elements listed in our internal $inlineElements list. This means that does not get tripped up by mid-paragraph HTML elements elements .
"... this text <em> IS REALLY</em> important to me ..." does not end up with non-breaking spaces added before the
<em> which would be undesirable. This is because tags like
<em> are recognized and treated like another DOMText node and grouped with the previously detected nodes. Only when it hits the actual end of the node collection or a block level element is encountered the buffered node collection will be processed.