option to show all partners even if customer or supplier are selected

certain forms require a partner which is defeined as supplier or customer
if customer is needed and only supplier is checked, the user does not see that the partner exists and will create a new one.
at a later point in time the duplicate parter is detected and a merge function is needed.
Hence IMHO it should be possible to display all partners in a second step even if customer or supplier is set in the form.