firefox + scroll wheel troubles

i recently updated my firefox to the latest version (1.5).  prior to this, i closed all my browser windows by clicking the scroll wheel of my mouse.  this no longer works.  is this an irreconcilable conflict between firefox and MS intellipoint (which i use), or can the situation be fixed?

clicking the scrollwheel to close the windows is not a feature of firefox. it's either a thing with your mouse software, or you had some extension to do it. i'm thinking mouse software though