i have often the case : some message are not displayed, when i click on heaader, no message, just white arez.
i found the cause today : the utf8_decode funtion do not work in readmessage_inc.php.
then i create a function called utf8_bis_decode ($text) with this line :
and replace all occurence of php function utf8_decode by utf8_bis_decode function.
now, all is displayed ! ;-)
happy to contribute,
TéJi from belgium