strange leak in instruments

When a luch instruments i have a leak that appear in the code below. where is the leak please ????

 - (void) viewWillAppear:(BOOL)animated 
{
    [NavBarStyles sharedInstance].navStyle = @"navBarImage.png";
    self.navigationController.navigationBar.barStyle = UIBarStyleDefault;


    self.navigationController.navigationBar.tintColor = [UIColor clearColor];
    self.navigationController.navigationBar.barStyle = UIBarStyleDefault;
    self.navigationController.navigationBar开发者_JAVA百科.tintColor = [UIColor colorWithRed:16/255.0 green:160/255.0 blue:177/255.0 alpha:1.0];


    [super viewWillAppear:animated];
}