While uploads cannot be done via Ajax, this is not true for custom progress measurement. There are several scenarios in monitoring custom progress via Ajax:
1) Having RadProgressManager and RadProgressArea updated by the RadAjaxManager/RadAjaxPanel/UpdatePanel - RadProgressManager andRadProgressArea will be recreated (the progress area will flicker)when the Ajax call has finished. Due to this refresh the progress measurement (the progress-Ajax calls) will stop automatically.
2) Having only operation-specific controls, but not RadProgressManager/RadProgressArea updated(e.g. a button and a label) - RadProgressArea will not flicker when the page update finishes.However, the progress-Ajax calls will continue and the time label of the progress area will continue counting. To stop this the RadProgressContext.Current.OperationComplete member should be set to True. The progress polling will stop automatically.