Problems with 32-bit Unicode codepoints

[Andrew Pantyukhin]

It appears screen does not cope with 32-bit Unicode codepoints
(actually anything more than FFFF). I can view them in urxvt
without screen, but not in a screen session. My environment is
fully UTF-8.

A quick way to test it is to install the Code2001 font (free,
easily googlable) and open this page in a capable text browser
(w3m works for me, otherwise use wget+cat):
   http://www.code2000.net/oneplane.htm

According to urxvt, all the 32-bit symbols are replaced with
codepoint U+FFFD (Unicode replacement character), but it may well
be that the symbols are just randomly corrupted and urxvt does
the replacing.

Any thoughts and advice will be appreciated.

Thanks!