WackoWiki

View source for Re: How to add custom HTML element to code.php

Looks good.

Not working in what way?
Not working at all or still uses the previous syntax?
%%(info type="warning")
Use **LF** not **CRLF** line endings in WackoWiki templates.
%%
You have to reparse the page, e.g. edit it again or empty ##body_r##, a formatter is not dynamic like an action.
Once it is parsed the result is stored in the ##body_r## field in the page table.

Did you tried to do a small change and save it again.
And purged the old cache on the server as well the browser.

When it still uses the previous version maybe you edited the wrong file (in the wrong instance) or updated the wrong file on the server. The template is the only source for the formatter.