REad up at www.shimano.com on the functions of your shift levers. Most likely, the extra click you are feeling is the trim function. It's also possible that your bike was set up to use the last two main shift positions of a triple shifter rather than the first two. If that's the case, there is a fix and those same tech documents will explain how to do it. www.parktool.com is another good resource for front derailler set up.