Dinh Thanh, hello!
Your addon does not work with russian #tags.
I made a small change:
/library/Tinhte/XenTag/BbCode/Formatter/AutoHashtag.php
/*
if (preg_match('/[^a-zA-Z0-9]/', $stringForPregMatch, $matches, PREG_OFFSET_CAPTURE))
{
$nonTagTextPos = $matches[0][1];
}
else
{
// get all of the...