Simon, I think all HTML is ignored by the adp parser. If you want to comment out code using the templating system, try using:
<if 0 eq 1>
unprocessed code, will not appear on user page
</if>
OTOH, I have previously proposed creating a comment tag for the templaiting system, for comments that should not be shown to the end user even in the source. You could do this in either tcl, with a new template tag, or with the built in tag proc.
proc comment_proc {string tagset} {
return
}
ns_register_adptag comment /comment comment_proc
# example:
<comment>This is a comment</comment>
