Okay. I opened Sigil with a blank epub. I copy/pasted the following into the blank epub:
Code:
<body>
<p>This<i> </i>is<i> </i>an<i> </i>italic<i> </i>sentence.</p>
</body>
I ran CustomCleanerPlus and clicked the Clear All button and then clicked on OK twice. After CC+ completed, the epub now looked like with the extra blank lines and the <i> </i> showing as <i/>:
Code:
</head>
<body>
<p>This<i/>is<i/>an<i/>italic<i/>sentence.</p>
</body>
</html>
Again, it is not adding the <i></i>, it is replacing <i> </i> with <i/>.