Here is an issue we ran into on the last project:

  1. On a Publishing Site, edit a page and add any webpart to an HTML Content Place Holder.
  2. In the chrome title bar, click delete on that web part
  3. Switch to view HTML Source and you should see the following HTML block that remains behind on the page:
<div class="ms-rtestate-read ms-rte-wpbox" contenteditable="false"><div class="ms-rtestate-notify  ms-rtestate-read c861ffc3-62f5-44a8-925a-a66af357e09f" id="div_c861ffc3-62f5-44a8-925a-a66af357e09f" unselectable="on"></div>
<div id="vid_c861ffc3-62f5-44a8-925a-a66af357e09f" unselectable="on" style="display: none"></div></div>

This issue is very weird. There should be nothing left behind after a web part is removed. Has anyone else out there run into this issue before?