在地图上拖动UIScrollView时，MKMapView addAnnotation延迟

I'm working on an iPad application and I have a full screen MKMapView with a transparent UIScrollView (about 1/5 of the screen) on top of it. I'm adding annotations (map pins) to the map as you horizontally scroll the UIScrollView, but I'm noticing that the pins don't actually drop onto the map until you release/stop dragging the UIScrollView.I'm working on an iPad application and I have a