question: protected synchronized void updateLocation ( Point newLocn ) { prev = locn ; locn = newLocn ; if ( Math . abs ( locn . x - prev . x ) > hysteresis || Math . abs ( locn . y - prev . y ) > hysteresis ) { if ( timer . isRunning ( ) ) timer . stop ( ) ; } else { if ( ! timer . isRunning ( ) ) timer . start ( ) ; } }
target:  cause autoscroll to occur <P>