Hi Ramakrushnarao,
Did you read this page? It details how the various Events are triggered. The On After Fetch isn't "stopped", it's run whenever the Aggregate is finished loading. In an On After Fetch, you are supposed to manipulate the data or set some Local Variables specific to the display of the data. It should not matter whether the On Ready Event has been triggered already or not.
That said, if for some reason the On After Fetch must really be triggered after the On Ready has been triggered, you should set the Aggregates to On Demand and Refresh them in the On Ready handler. The downside is that it will take longer for the data to become available.