diff -u RackTables-0.19.12/wwwroot/inc/functions.php RackTables-0.19.12_patched/wwwroot/inc/functions.php
--- RackTables-0.19.12/wwwroot/inc/functions.php	2012-03-14 13:58:35.000000000 +0100
+++ RackTables-0.19.12_patched/wwwroot/inc/functions.php	2012-06-27 11:58:44.345376128 +0200
@@ -1341,7 +1341,8 @@
 	$ret = array();
 	foreach (array_unique ($tagidlist) as $tag_id)
 		if (isset ($taglist[$tag_id]))
-			$ret[] = $taglist[$tag_id];
+			if( substr($taglist[$tag_id]['tag'],0,1) != '-')
+				$ret[] = $taglist[$tag_id];
 	return $ret;
 }
 
diff -u RackTables-0.19.12/wwwroot/inc/interface-lib.php RackTables-0.19.12_patched/wwwroot/inc/interface-lib.php
--- RackTables-0.19.12/wwwroot/inc/interface-lib.php	2012-03-14 13:58:35.000000000 +0100
+++ RackTables-0.19.12_patched/wwwroot/inc/interface-lib.php	2012-06-27 11:58:44.359385169 +0200
@@ -4,7 +4,7 @@
 # framework. See accompanying file "COPYING" for the full copyright and
 # licensing information.
 
-define ('TAGNAME_REGEXP', '/^[\p{L}0-9]([. _~-]?[\p{L}0-9])*$/u');
+define ('TAGNAME_REGEXP', '/^-?[\p{L}0-9]([. _~-]?[\p{L}0-9])*$/u');
 define ('AUTOTAGNAME_REGEXP', '/^\$[\p{L}0-9]([. _~-]?[\p{L}0-9])*$/u');
 
 // Let's have it here, so extensions can add their own images.
diff -u RackTables-0.19.12/wwwroot/inc/interface.php RackTables-0.19.12_patched/wwwroot/inc/interface.php
--- RackTables-0.19.12/wwwroot/inc/interface.php	2012-04-10 15:55:23.000000000 +0200
+++ RackTables-0.19.12_patched/wwwroot/inc/interface.php	2012-06-27 11:58:44.394380764 +0200
@@ -5857,8 +5857,10 @@
 	$tr_class = ($level == 0 && $taginfo['id'] > 0 && !$is_first_time ? 'separator' : '');
 	$is_first_time = FALSE;
 	
+	$isgroup = substr($taginfo['tag'],0,1) == '-';
+	
 	echo "<tr class='$tr_class'><td colspan=2 class='$td_class' style='padding-left: " . ($level * 16) . "px;'>";
-	echo "<label><input type=checkbox class='$input_class' name='${prepared_inputname}[]' value='${taginfo['id']}'" . ($selected ? ' checked' : '') . "> ";
+	echo "<label>".($isgroup ? "" : "<input type=checkbox class='$input_class' name='${prepared_inputname}[]' value='${taginfo['id']}'" . ($selected ? ' checked' : '') . "> ");
 	echo $taginfo['tag'];
 	if (strlen ($refcnt_realm) and isset ($taginfo['refcnt'][$refcnt_realm]))
 		echo ' <i>(' . $taginfo['refcnt'][$refcnt_realm] . ')</i>';