[BirdOPrey5]

Basically you go to the plugin named "Forum Display"

Look through the code, look for all instances if $forumid and change it to something else, like $forumidx

If you want this is the entire plugin with the variable name changed to $forumidz

// Hide any non-matching categories and forums by removing them from our in-memory copy of the forum cache

    // Don't alter the forumcache if we're somewhere that it would mess things up.
    if(THIS_SCRIPT == 'subscription' || THIS_SCRIPT == 'usercp' || THIS_SCRIPT == 'inlinemod') {
        $alterState = FALSE;
    } else {
        $alterState = TRUE;
    }

    global $vbulletin;
    global $ib_match_found;
    global $ib_category_ids;
    global $ib_valid_forumids;
        global $vb_cerberus_options;

if(THIS_SCRIPT == 'search' && $vb_cerberus_options['search']['search_global'] == TRUE)
{
      $alterState = FALSE;
}


    $vbulletin->userinfo['forumpermissions_orig'] = $vbulletin->userinfo['forumpermissions'];
    $can_view = 524288; // 0008:0000h
    $forumids = array();
    $vbulletin->forumcache_original = $vbulletin->forumcache;
    if($ib_match_found == TRUE) {
        foreach(array_keys($vbulletin->forumcache) as $forumidz) {
            // If there is no match between the visible categories and the parentlist
            // (which includes the current forumid), we don't display it

            $ib_checkforumids = explode(",", $vbulletin->forumcache[$forumidz]['parentlist']);

            $ib_intersection = array_intersect($ib_checkforumids, $ib_category_ids);

            $is_visible = $vbulletin->userinfo[forumpermissions][$forumidz] & $can_view;

            // If it's not in the list of valid forums for this domain, OR we can't view it, forget it exists
            if((count($ib_intersection) == 0 || $is_visible == 0) && !(THIS_SCRIPT == 'postings')) {
                if($alterState) {
                    //debug("Unset " . $vbulletin->forumcache[$forumidz][title]);
                    unset($vbulletin->forumcache[$forumidz]);
                    unset($vbulletin->iforumcache[$forumidz]);
                    unset($vbulletin->userinfo[forumpermissions][$forumidz]);
                }
            } else {
                //debug("+++ " . $vbulletin->forumcache[$forumidz][title]);
                $forumids []= $forumidz;
            }
        }
    }
    $ib_valid_forumids = join(",", $forumids);