xoops code/decode issue
The xoops module.textsanitizer.php is really fantastic script but buggy. some known items:
function codePreConv, codeConv: the pair of functions handling
function &undoHtmlSpecialChars(&$text), function &htmlSpecialChars($text):
  is converted to   in htmlSpecialChars but not converted back in undoHtmlSpecialChars, which took long time to debug quote problem for NewBB 2.
rendering
extended code? I published a hack for xoops extended code but it needs more work to make configurable for the flash or realplayer stuff could be annoying to some guys.