log4net使用时没有日志输出信息
配置文件如下，程序中Globals.sLog = LogManager.GetLogger("GUILogger");但是sLog的IsDebugEnabled等属性均为false.不知什么原因
<configuration>
    <configSections>
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
    </configSections>
    <log4net debug="false">
        <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender" Additivity="true">
            <file value="log.txt" />
            <appendToFile value="true" />
            <rollingStyle value="Composite" />
            <datePattern value=".yyyyMMdd" />
            <maxSizeRollBackups value="10" />
            <maximumFileSize value="4MB" />
            <staticLogFileName value="true" />
            <layout type="log4net.Layout.PatternLayout">             
                <ConversionPattern value="%date{yyyy-MM-dd HH:mm:ss.fff} %5level [%4thread] %-20logger - %message%newline" />
            </layout>
            
            <filter type="log4net.Filter.LevelRangeFilter">
                <levelMin value="DEBUG" />
                <levelMax value="FATAL" />
            </filter>
        </appender>
        
        <appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender" Additivity="true">
            <mapping>
                <level value="FATAL" />
                <foreColor value="Red, HighIntensity" />
            </mapping>
            <mapping>
                <level value="ERROR" />
                <foreColor value="Red" />
            </mappi