Hi,
What is $GLOBALS['convcharset'] needed for? I looked at the code and can't find any place where it can be changed by users (there is a line reading from $_REQUEST['convcharset']), but it is stored in a cookie pma_convcharset. From what I found, it is read from $cfg['DefaultCharset'] and is always 'utf-8' or whatever the $cfg variable tells if to be.