Got ACL scope logic working again and began enforcing it. Breaking API change: assigning page title with $template->tpl_strings['PAGE_NAME'] will no longer work, use $template->assign_vars(). Workaround may be added later. Test for assign_vars method if compatibility needed. Added namespace processor API (non-breaking change). Several other things tweaked around as well.
<!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>{#advimage_dlg.dialog_title}</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/validate.js"></script>
<script type="text/javascript" src="../../utils/editable_selects.js"></script>
<script type="text/javascript" src="js/image.js"></script>
<link href="css/advimage.css" rel="stylesheet" type="text/css" />
<base target="_self" />
</head>
<body id="advimage" style="display: none">
<form onsubmit="ImageDialog.insert();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;">{#advimage_dlg.tab_general}</a></span></li>
<li id="appearance_tab"><span><a href="javascript:mcTabs.displayTab('appearance_tab','appearance_panel');" onmousedown="return false;">{#advimage_dlg.tab_appearance}</a></span></li>
<li id="advanced_tab"><span><a href="javascript:mcTabs.displayTab('advanced_tab','advanced_panel');" onmousedown="return false;">{#advimage_dlg.tab_advanced}</a></span></li>
</ul>
</div>
<div class="panel_wrapper">
<div id="general_panel" class="panel current">
<fieldset>
<legend>{#advimage_dlg.general}</legend>
<table class="properties">
<tr>
<td class="column1"><label id="srclabel" for="src">{#advimage_dlg.src}</label></td>
<td colspan="2"><table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input name="src" type="text" id="src" value="" class="mceFocus" onchange="ImageDialog.showPreviewImage(this.value);" /></td>
<td id="srcbrowsercontainer"> </td>
</tr>
</table></td>
</tr>
<tr>
<td><label for="src_list">{#advimage_dlg.image_list}</label></td>
<td><select id="src_list" name="src_list" onchange="document.getElementById('src').value=this.options[this.selectedIndex].value;document.getElementById('alt').value=this.options[this.selectedIndex].text;document.getElementById('title').value=this.options[this.selectedIndex].text;ImageDialog.showPreviewImage(this.options[this.selectedIndex].value);"></select></td>
</tr>
<tr>
<td class="column1"><label id="altlabel" for="alt">{#advimage_dlg.alt}</label></td>
<td colspan="2"><input id="alt" name="alt" type="text" value="" /></td>
</tr>
<tr>
<td class="column1"><label id="titlelabel" for="title">{#advimage_dlg.title}</label></td>
<td colspan="2"><input id="title" name="title" type="text" value="" /></td>
</tr>
</table>
</fieldset>
<fieldset>
<legend>{#advimage_dlg.preview}</legend>
<div id="prev"></div>
</fieldset>
</div>
<div id="appearance_panel" class="panel">
<fieldset>
<legend>{#advimage_dlg.tab_appearance}</legend>
<table border="0" cellpadding="4" cellspacing="0">
<tr>
<td class="column1"><label id="alignlabel" for="align">{#advimage_dlg.align}</label></td>
<td><select id="align" name="align" onchange="ImageDialog.updateStyle('align');ImageDialog.changeAppearance();">
<option value="">{#not_set}</option>
<option value="baseline">{#advimage_dlg.align_baseline}</option>
<option value="top">{#advimage_dlg.align_top}</option>
<option value="middle">{#advimage_dlg.align_middle}</option>
<option value="bottom">{#advimage_dlg.align_bottom}</option>
<option value="text-top">{#advimage_dlg.align_texttop}</option>
<option value="text-bottom">{#advimage_dlg.align_textbottom}</option>
<option value="left">{#advimage_dlg.align_left}</option>
<option value="right">{#advimage_dlg.align_right}</option>
</select>
</td>
<td rowspan="6" valign="top">
<div class="alignPreview">
<img id="alignSampleImg" src="img/sample.gif" alt="{#advimage_dlg.example_img}" />
Lorem ipsum, Dolor sit amet, consectetuer adipiscing loreum ipsum edipiscing elit, sed diam
nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.Loreum ipsum
edipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam
erat volutpat.
</div>
</td>
</tr>
<tr>
<td class="column1"><label id="widthlabel" for="width">{#advimage_dlg.dimensions}</label></td>
<td nowrap="nowrap">
<input name="width" type="text" id="width" value="" size="5" maxlength="5" class="size" onchange="ImageDialog.changeHeight();" /> x
<input name="height" type="text" id="height" value="" size="5" maxlength="5" class="size" onchange="ImageDialog.changeWidth();" /> px
</td>
</tr>
<tr>
<td> </td>
<td><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><input id="constrain" type="checkbox" name="constrain" class="checkbox" /></td>
<td><label id="constrainlabel" for="constrain">{#advimage_dlg.constrain_proportions}</label></td>
</tr>
</table></td>
</tr>
<tr>
<td class="column1"><label id="vspacelabel" for="vspace">{#advimage_dlg.vspace}</label></td>
<td><input name="vspace" type="text" id="vspace" value="" size="3" maxlength="3" class="number" onchange="ImageDialog.updateStyle('vspace');ImageDialog.changeAppearance();" onblur="ImageDialog.updateStyle('vspace');ImageDialog.changeAppearance();" />
</td>
</tr>
<tr>
<td class="column1"><label id="hspacelabel" for="hspace">{#advimage_dlg.hspace}</label></td>
<td><input name="hspace" type="text" id="hspace" value="" size="3" maxlength="3" class="number" onchange="ImageDialog.updateStyle('hspace');ImageDialog.changeAppearance();" onblur="ImageDialog.updateStyle('hspace');ImageDialog.changeAppearance();" /></td>
</tr>
<tr>
<td class="column1"><label id="borderlabel" for="border">{#advimage_dlg.border}</label></td>
<td><input id="border" name="border" type="text" value="" size="3" maxlength="3" class="number" onchange="ImageDialog.updateStyle('border');ImageDialog.changeAppearance();" onblur="ImageDialog.updateStyle('border');ImageDialog.changeAppearance();" /></td>
</tr>
<tr>
<td><label for="class_list">{#class_name}</label></td>
<td colspan="2"><select id="class_list" name="class_list" class="mceEditableSelect"></select></td>
</tr>
<tr>
<td class="column1"><label id="stylelabel" for="style">{#advimage_dlg.style}</label></td>
<td colspan="2"><input id="style" name="style" type="text" value="" onchange="ImageDialog.changeAppearance();" /></td>
</tr>
<!-- <tr>
<td class="column1"><label id="classeslabel" for="classes">{#advimage_dlg.classes}</label></td>
<td colspan="2"><input id="classes" name="classes" type="text" value="" onchange="selectByValue(this.form,'classlist',this.value,true);" /></td>
</tr> -->
</table>
</fieldset>
</div>
<div id="advanced_panel" class="panel">
<fieldset>
<legend>{#advimage_dlg.swap_image}</legend>
<input type="checkbox" id="onmousemovecheck" name="onmousemovecheck" class="checkbox" onclick="ImageDialog.setSwapImage(this.checked);" />
<label id="onmousemovechecklabel" for="onmousemovecheck">{#advimage_dlg.alt_image}</label>
<table border="0" cellpadding="4" cellspacing="0" width="100%">
<tr>
<td class="column1"><label id="onmouseoversrclabel" for="onmouseoversrc">{#advimage_dlg.mouseover}</label></td>
<td><table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="onmouseoversrc" name="onmouseoversrc" type="text" value="" /></td>
<td id="onmouseoversrccontainer"> </td>
</tr>
</table></td>
</tr>
<tr>
<td><label for="over_list">{#advimage_dlg.image_list}</label></td>
<td><select id="over_list" name="over_list" onchange="document.getElementById('onmouseoversrc').value=this.options[this.selectedIndex].value;"></select></td>
</tr>
<tr>
<td class="column1"><label id="onmouseoutsrclabel" for="onmouseoutsrc">{#advimage_dlg.mouseout}</label></td>
<td class="column2"><table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="onmouseoutsrc" name="onmouseoutsrc" type="text" value="" /></td>
<td id="onmouseoutsrccontainer"> </td>
</tr>
</table></td>
</tr>
<tr>
<td><label for="out_list">{#advimage_dlg.image_list}</label></td>
<td><select id="out_list" name="out_list" onchange="document.getElementById('onmouseoutsrc').value=this.options[this.selectedIndex].value;"></select></td>
</tr>
</table>
</fieldset>
<fieldset>
<legend>{#advimage_dlg.misc}</legend>
<table border="0" cellpadding="4" cellspacing="0">
<tr>
<td class="column1"><label id="idlabel" for="id">{#advimage_dlg.id}</label></td>
<td><input id="id" name="id" type="text" value="" /></td>
</tr>
<tr>
<td class="column1"><label id="dirlabel" for="dir">{#advimage_dlg.langdir}</label></td>
<td>
<select id="dir" name="dir" onchange="ImageDialog.changeAppearance();">
<option value="">{#not_set}</option>
<option value="ltr">{#advimage_dlg.ltr}</option>
<option value="rtl">{#advimage_dlg.rtl}</option>
</select>
</td>
</tr>
<tr>
<td class="column1"><label id="langlabel" for="lang">{#advimage_dlg.langcode}</label></td>
<td>
<input id="lang" name="lang" type="text" value="" />
</td>
</tr>
<tr>
<td class="column1"><label id="usemaplabel" for="usemap">{#advimage_dlg.map}</label></td>
<td>
<input id="usemap" name="usemap" type="text" value="" />
</td>
</tr>
<tr>
<td class="column1"><label id="longdesclabel" for="longdesc">{#advimage_dlg.long_desc}</label></td>
<td><table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="longdesc" name="longdesc" type="text" value="" /></td>
<td id="longdesccontainer"> </td>
</tr>
</table></td>
</tr>
</table>
</fieldset>
</div>
</div>
<div class="mceActionPanel">
<div style="float: left">
<input type="submit" id="insert" name="insert" value="{#insert}" />
</div>
<div style="float: right">
<input type="button" id="cancel" name="cancel" value="{#cancel}" onclick="tinyMCEPopup.close();" />
</div>
</div>
</form>
</body>
</html>