<p>This tests inserting a line break at the end of a tab span.  Below you should see 'foo' followed by an empty paragraph, with the caret in it.</p>
<div id="div" contenteditable="true">foo<span class="Apple-tab-span" style="white-space:pre">	</span></div>
    
<script>
div = document.getElementById("div");
sel = window.getSelection();
sel.setPosition(div, div.childNodes.length);
document.execCommand("InsertLineBreak");
</script>