Firefox Issue with Lists

Trying to exec a list with only one line, or selecting all the text results in an error: "NS_ERROR_FAILURE: Failure" 2147500037

HTML

<button data-command="insertOrderedList">OL</button>
<button data-command="insertUnorderedList">UL</button>
<article contenteditable></article>

CSS

article {
    border:1px solid #CCC;
    min-height:50px;
}

JavaScript

var editor = $(document.body).getFirst('article');
$(document.body).addEvent('click:relay(button[data-command)', function(e, target){
    //editor.focus();
    document.execCommand(target.get('data-command'), false);
});