Have you found a solution for your problem i am having the same problem.

kind regards.

This is a filter for sales orders which shows me orders within 30 days.  Again, I am trying to show a list of customers who do not have any active orders within a specified time period.  I can run a filter on sales orders older than 30 days, and group by customer, but this doesnt help because it will still include customers which might have an active order from 1-2 days ago, it will just only show their old orders.  I hope this makes sense.

<filter string="Last 30 Days" name="prev_month" domain="[('date_order','&gt;=',(context_today()-relativedelta(months=1)).strftime('%Y-%m-01')),('date_order','&lt;',time.strftime('%Y-%m-01'))]"/>

Add this filter in your search view in sale order.check this :), I've changed my answer.but this will only filtered last 30 days customers.