fixed bug introduced by latest firebug version
fixed bug introduced by latest firebug version

arjunrn/yslow,wangyi8412/yslow,simudream/yslow,aaron-goshine/yslow,aaron-goshine/yslow,arjunrn/yslow,wangyi8412/yslow,codeviking/yslow,marcelduran/yslow,codeviking/yslow,simudream/yslow