I come across many strangely used isset(..) syntax in many files, mainly in the scripts folder:
PHP Code

	$BodySig = $Body;
	isset($user['USER_AVATAR']) && $Picture = $user['USER_AVATAR'];
	if (!isset($Picture)) { $Picture = "http://"; }

Just look at the second line. And there are many more like these throughout the code.
I cannot help think that this must be remainders of old if(...) statements. Can you explain what is supposed to happen here?