Added a copy of Firebug Lite for debugging purposes. License is uncertain but being treated as MPL. (If is is not MPL then it is under something more permissive that permits relicensing anyway)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>{#xhtmlxtras_dlg.title_del_element}</title>
<script type="text/javascript" src="../../tiny_mce_popup.js"></script>
<script type="text/javascript" src="../../utils/mctabs.js"></script>
<script type="text/javascript" src="../../utils/form_utils.js"></script>
<script type="text/javascript" src="../../utils/editable_selects.js"></script>
<script type="text/javascript" src="js/element_common.js"></script>
<script type="text/javascript" src="js/del.js"></script>
<link rel="stylesheet" type="text/css" href="css/popup.css" />
<base target="_self" />
</head>
<body id="xhtmlxtrasins" style="display: none">
<form onsubmit="insertDel();return false;" action="#">
<div class="tabs">
<ul>
<li id="general_tab" class="current"><span><a href="javascript:mcTabs.displayTab('general_tab','general_panel');" onmousedown="return false;">{#xhtmlxtras_dlg.general_tab}</a></span></li>
<!-- <li id="events_tab"><span><a href="javascript:mcTabs.displayTab('events_tab','events_panel');" onmousedown="return false;">{#xhtmlxtras_dlg.events_tab}</a></span></li> -->
</ul>
</div>
<div class="panel_wrapper">
<div id="general_panel" class="panel current">
<fieldset>
<legend>{#xhtmlxtras_dlg.fieldset_general_tab}</legend>
<table border="0" cellpadding="0" cellspacing="4">
<tr>
<td class="label"><label id="datetimelabel" for="datetime">{#xhtmlxtras_dlg.attribute_label_datetime}</label>:</td>
<td>
<table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="datetime" name="datetime" type="text" value="" maxlength="19" class="field" /></td>
<td><a href="javascript:insertDateTime('datetime');" onmousedown="return false;" class="browse"><span class="datetime" alt="{#xhtmlxtras_dlg.insert_date}" title="{#xhtmlxtras_dlg.insert_date}"></span></a></td>
</tr>
</table>
</td>
</tr>
<tr>
<td class="label"><label id="citelabel" for="cite">{#xhtmlxtras_dlg.attribute_label_cite}</label>:</td>
<td><input id="cite" name="cite" type="text" value="" class="field" /></td>
</tr>
</table>
</fieldset>
<fieldset>
<legend>{#xhtmlxtras_dlg.fieldset_attrib_tab}</legend>
<table border="0" cellpadding="0" cellspacing="4">
<tr>
<td class="label"><label id="titlelabel" for="title">{#xhtmlxtras_dlg.attribute_label_title}</label>:</td>
<td><input id="title" name="title" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label id="idlabel" for="id">{#xhtmlxtras_dlg.attribute_label_id}</label>:</td>
<td><input id="id" name="id" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label id="classlabel" for="class">{#xhtmlxtras_dlg.attribute_label_class}</label>:</td>
<td>
<select id="class" name="class" class="field mceEditableSelect">
<option value="">{#not_set}</option>
</select>
</td>
</tr>
<tr>
<td class="label"><label id="stylelabel" for="class">{#xhtmlxtras_dlg.attribute_label_style}</label>:</td>
<td><input id="style" name="style" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label id="dirlabel" for="dir">{#xhtmlxtras_dlg.attribute_label_langdir}</label>:</td>
<td>
<select id="dir" name="dir" class="field">
<option value="">{#not_set}</option>
<option value="ltr">{#xhtmlxtras_dlg.attribute_option_ltr}</option>
<option value="rtl">{#xhtmlxtras_dlg.attribute_option_rtl}</option>
</select>
</td>
</tr>
<tr>
<td class="label"><label id="langlabel" for="lang">{#xhtmlxtras_dlg.attribute_label_langcode}</label>:</td>
<td>
<input id="lang" name="lang" type="text" value="" class="field" />
</td>
</tr>
</table>
</fieldset>
</div>
<div id="events_panel" class="panel">
<fieldset>
<legend>{#xhtmlxtras_dlg.fieldset_events_tab}</legend>
<table border="0" cellpadding="0" cellspacing="4">
<tr>
<td class="label"><label for="onfocus">onfocus</label>:</td>
<td><input id="onfocus" name="onfocus" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onblur">onblur</label>:</td>
<td><input id="onblur" name="onblur" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onclick">onclick</label>:</td>
<td><input id="onclick" name="onclick" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="ondblclick">ondblclick</label>:</td>
<td><input id="ondblclick" name="ondblclick" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onmousedown">onmousedown</label>:</td>
<td><input id="onmousedown" name="onmousedown" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onmouseup">onmouseup</label>:</td>
<td><input id="onmouseup" name="onmouseup" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onmouseover">onmouseover</label>:</td>
<td><input id="onmouseover" name="onmouseover" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onmousemove">onmousemove</label>:</td>
<td><input id="onmousemove" name="onmousemove" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onmouseout">onmouseout</label>:</td>
<td><input id="onmouseout" name="onmouseout" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onkeypress">onkeypress</label>:</td>
<td><input id="onkeypress" name="onkeypress" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onkeydown">onkeydown</label>:</td>
<td><input id="onkeydown" name="onkeydown" type="text" value="" class="field" /></td>
</tr>
<tr>
<td class="label"><label for="onkeyup">onkeyup</label>:</td>
<td><input id="onkeyup" name="onkeyup" type="text" value="" class="field" /></td>
</tr>
</table>
</fieldset>
</div>
</div>
<div class="mceActionPanel">
<div style="float: left">
<input type="button" id="insert" name="insert" value="{#update}" onclick="insertDel();" />
</div>
<div style="float: left">
<input type="button" id="remove" name="remove" class="button" value="{#xhtmlxtras_dlg.remove}" onclick="removeDel();" style="display: none;" />
</div>
<div style="float: right">
<input type="button" id="cancel" name="cancel" value="{#cancel}" onclick="tinyMCEPopup.close();" />
</div>
</div>
</form>
</body>
</html>