[rules-users] Delete a List of Facts

Hi, I want to delete a list of facts from the working memory and therefore created following rule: rule "delete rule" agenda-group "evaluation" salience 50 no-loop true when $facts : ArrayList(size > 0) from collect (Fact()) then logger.info("delete rule, number of facts in list: " + $facts.size()); for (int i = 0; i < $facts.size(); i++) { Fact f = (Fact)$facts.get(i); logger.info("retract fact id: " + f.getId()); retract(f); } end When inserting 10 facts with IDs 1 to 10 and then fire all rules, I get following result: delete rule, number of facts in list: 10 retract fact id: 1 retract fact id: 3 retract fact id: 5 retract fact id: 7 retract fact id: 9 but, the facts 2, 4, 6, 8 and 10 are not deleted. I would have expected to set "no-loop" to true, as I do some modification of facts and don't want that this rule is fired again with the same facts. When I set "no-loop" to false, I get following result: delete rule, number of facts in list: 10 retract fact id: 1 retract fact id: 3 retract fact id: 5 retract fact id: 7 retract fact id: 9 delete rule, number of facts in list: 5 retract fact id: 2 retract fact id: 6 retract fact id: 10 delete rule, number of facts in list: 2 retract fact id: 4 delete rule, number of facts in list: 1 retract fact id: 8 now, all facts are deleted but the "delete rule" was fired 4 times. Is this the intended behavior of Drools? Is there a way to fire a rule only once and delete a list of facts? I can reproduce this behavior with Drools 5.5.0.Final and 6.0.0.Beta2 but did not try any other version. Best Regards, Wolfgang