Check the "Tips & Tricks" page of the AmiKit website:
"Don't you like the blue rotating arrow? Run Exchange (press LeftAmiga+e) and quit the ?BoingBall? task. Or disable it permanetly: Use WBStartup+Prefs program (click the boingball located at taskbar -> Tools -> System -> WBStartup+Prefs) and untick ?BoingBall?. If you want to change the position of the arrow only, edit AmiKit:Prefs/Presets/AmiKit/BoingBall/boingball_Arrow.config file."