This feature depends on the template. If you look at your URL forum, there's an extra field which is "expv". I love to include this as a feature but not all templates are created wisely. It's just impossible for this to be a configurable feature.
If you are good in PHP, you may be able to modify your template to do this. If you are not, you can wait until I release template that makes use of this.
Here are the code details:
expv=0 - menu mode
expv=1 - wide mode
expv=2 - full screen mode
These points refer to my template only:
displays left menu if expv=0, hide if expv=1 or 2
<?php if ( mosCountModules("left") && $_REQUEST['expv'] == 0) { ?>
<td width="150" valign="top" height="100%">
<table class="moduletable-left" border="0" align="center" cellspacing="0" cellpadding="2" height="100%">
<tr><td valign="top"><?php mosLoadModules("left"); ?></td></tr>
</table>
</td>
<?php } ?>
adds the link on top of pathway "Wide | Full | Menu"
<?php
$pos = strpos($_SERVER['REQUEST_URI'],"&expv=");
$wide = ($pos >= 0 && !($pos === false) ? preg_replace("/&expv=[0-2]/s",'',$_SERVER['REQUEST_URI']) . "&expv=1" : $_SERVER['REQUEST_URI']."&expv=1");
$full = ($pos >= 0 && !($pos === false) ? preg_replace("/&expv=[0-2]/s",'',$_SERVER['REQUEST_URI']) . "&expv=2" : $_SERVER['REQUEST_URI']."&expv=2");
$short = (($pos >= 0 && !($pos === false) || $pos === false) ? preg_replace("/&expv=[0-2]/s",'',$_SERVER['REQUEST_URI']) . "&expv=0" : $_SERVER['REQUEST_URI']."&expv=0");
if ($mosConfig_sef == '1') {
$wide = sefRelToAbs(substr($wide,1,strlen($wide)));
$full = sefRelToAbs(substr($full,1,strlen($full)));
$short = sefRelToAbs(substr($short,1,strlen($short)));
}
$expand = $_REQUEST['option'] != "com_smf" ? '' : '<table class="expandtext" width="100%" align="center"><tr><td width="100%" align="center"><a href="'.$wide.'" class="expandtext">Wide View</a> | <a href="'.$full.'" class="expandtext">Full View</a> | <a href="'.$short.'" class="expandtext">Menu View</a></td></tr></table>';
?>
<br /><?php echo $expand; ?><div id="pathway_outline">
<div id="pathway"><?php mosPathWay(); ?></div>
makes it full screen if expv=2
<?php $main = ob_get_contents(); ob_end_clean(); MH_get_layout($main,($_REQUEST['expv'] == 2 ? "99%" : "760")); ?>