Index: branches/RC/core/units/categories/categories_item.php
===================================================================
diff -u -r11501 -r11610
--- branches/RC/core/units/categories/categories_item.php	(.../categories_item.php)	(revision 11501)
+++ branches/RC/core/units/categories/categories_item.php	(.../categories_item.php)	(revision 11610)
@@ -78,8 +78,13 @@
 		function checkFilename()
 		{
 			if ($this->GetDBField('AutomaticFilename')) {
+				// filename will be generated from scratch, don't check anything here
 				return ;
 			}
+			elseif ($this->GetDBField('IsSystem')) {
+				// system page with AutomaticFilename checkbox unchecked -> compatibility with Proj-CMS <= 4.3.9 (when "/" were allowed in Filename)
+				return ;
+			}
 
 			$filename = $this->GetDBField('Filename');
 			$this->SetDBField('Filename', $this->stripDisallowed($filename));