Castle Windsor IOC和配置文件中的外观顺序

I'm new to Castle Windsor and am confused about the order in the config file. This is taken from the GettingStarted1 sample. The HttpServiceWatcher class takes an IFailureNotifier implementor in it's constructor. However, no matter how I order the two components that implement this interface -- AlarmFailureNotifier and EmailFailureNotifier -- I always get EmailFailureNotifier. I know you can override which is chosen using parameters and a "service lookup" reference, but I thought that the order of declaration is used when other mechanisms are not.I'm new to Castle Windsor and am confused about