rem: fp.setFilters(nsIFilePicker.filterAll); 
add: fp.appendFilters(nsIFilePicker.filterAll); 
context: function PrefCacheSelectFolder() {    // Get filespecwithui component.       try {    var fp = Components.classes["component://mozilla/filepicker"].createInstance(nsIFilePicker);    /* XXX    no title here */    fp.init(window, "", nsIFilePicker.modeGetFolder);    fp.setFilters(nsIFilePicker.filterAll);    fp.show();    var field = document.getElementById("pref:string:browser.cache.directory");    field.setAttribute("value", fp.file.unicodePath);  } catch(ex) { }}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/2804c173c560ade19a248b6f40dac0f2b5e0587d/PrefsWindow.js/clean/xpfe/components/prefwindow/resources/content/PrefsWindow.js