                    pointermove_events.set(event.pointerId, event);
                    }
                });

                on_event(target0, "pointerdown", function (event) {
                    assert_equals(event.isPrimary, !!(pointerdown_events.size == 0), "pointerdown.isPrimary should only be true for first pointer.");
                    pointerdown_events.set(event.pointerId, event);
                    detected_pointertypes[event.pointerType] = true;
                });

                on_event(