I found out where the problem could be.....in program/steps/mail/func.inc I've commented out $body = $IMAP->charset_decode($body, $parameters); and the whole message displays like it should. But if I try to force iso-8859-2 in main.inc.php ($rcmail_config['charset'] = 'iso-8859-2';) the mail again doesn't display like it should....and it doesn't matter if I use charset_decode or not.
what else can I try?
example of the e-mail (the original message):
PD NEMO in Potapljaški center Murena organizirata organizirano potapljanje v Sv.
Marini pri Rabcu.
roundcubemail only displays:
PD NEMO in Potaplja