<template name="matrix_result_extended" inherit_id="survey.result_ matrix">
<xpath expr="." position="replace">
<!-- custom code here to replace all template code -->
</xpath>
</template>
But it seems that it doesn't work, because the parent result_matrix is not recognized by the qweb engine anymore when trying to render the survey results.
Is there a clean way to replace all code template by a completely new one ?