gistfile1

- (void)mouseDragged:(NSEvent *)anEvent
{
    [NSEvent startPeriodicEventsAfterDelay:2.0 withPeriod:0.1];

    NSEvent *ev = nil;
    BOOL continueTracking = YES;
    
    do
    {
        ev = [[self window] nextEventMatchingMask: NSLeftMouseUpMask | NSLeftMouseDraggedMask | NSPeriodicMask];
        NSLog(@"PERIODIC EVENT: %@", ev);
        switch ([ev type])
        {
            case NSLeftMouseDragged:
                continueTracking = NO;
                break;
            case NSLeftMouseUp:
                continueTracking = NO;
                break;
            case NSPeriodicMask:
                [self autoscroll:anEvent];
                break;
        }
    } while (continueTracking);

    [NSEvent stopPeriodicEvents];
}