I created an extra column and added icons at the end of the list for editing and deleting an event.
Here is what I have
<g:form id="${it.id}">
<span class="simple">
<g:actionSubmit class="editar" action="edit"
value="${message(code:'default.button.editar.label',
default: ' ')}" />
</span>
<span class="simple">
<g:actionSubmit class="eliminar" action="delete"
value="${message(code: 'default.button.eliminar.label',
default: ' ')}"
onclick="return confirm('${message(code: 'default.button.delete.confirm.message', default: 'Esta seguro que desea Eliminar?')}');" />
</span>
</g:form>
In summary: replace the value="${it.id}" in your g:form tag with id="{it.id}" and remove the hiddenField for ID. I think that will correct the problem.
Let me know if it doesn't work...