In my Version of LimeWire there are only two icons at the bottom left of the Library window. That is: Refresh and Explore.
If you have and extra icon I would suggest That somehow your LimeWire version has become corrupted. I would check to make sure all your songs are still in the directory that you have assigned as your sharing directory and any other directory that has files you may not be sharing to make sure they are all still there.
Then I would un-install LimeWire, ( including going into C:\ Program Files and deleting the LimeWire folder from in there) then obtain the latest full release which is 4.16.6 (making sure to get it from the genuine LimeWire homepage) and re-install LimeWire and see what happens.