Under what browser you are experiencing this behavior? This is most probably a browser behavior, because RadAjax has nothing to do with the scrolling feature of the browser. If you want to scroll the content after a partial postback the logic should be custom written. IE has a known bug with scrolling, check if this is behavior is reproduced in the other browsers too.
About the other question, RadAjaxLoading panel is shown only during the Ajax request, if the request is too short the LoadingPanel may not be showed. However, you could change this behavior by setting the InitialDelayTime and the MinDisplayTime. More information about these two properties could be found in this
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