rem: if (!filterList) return; if (!filter) return; 
add: if (!filterList || !filter) return; 
context: function moveCurrentFilter(motion){    var filterList = currentFilterList();    var filter = currentFilter();    if (!filterList) return;    if (!filter) return;    filterList.moveFilter(filter, motion);    refreshFilterList();}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/03f8d406f8d7b80d4de01dffbecfac3f6e2854e0/FilterListDialog.js/buggy/mailnews/base/search/resources/content/FilterListDialog.js