>>Please see attached image,
>>
>>I had to put the sequence Quote + Less than inside a PRE tag to save or update the message.
>
>Sign starts a HTML tag and not all tags are allowed for security.
>Use < that is, without spaces, & l t ;

Thank you, Lutz, I forgot about that. Was trying to write "<?", and forgot that the LE engine would interpret this as a HTML tag.

Nevertheless, a warning message would be welcome, instead of a silent no-can-do.