rem: var defaultResolution = document.getElementById("defaultResolution"); screenResolution.selectedItem = defaultResolution; userResolution.setAttribute("hidden", "true"); 
add:  screenResolution.selectedItem = previousSelection; 
context: function changeScreenResolution()  {    var screenResolution = document.getElementById("screenResolution");    var userResolution = document.getElementById("userResolution");      if (screenResolution.value == "other")      {        // If the user selects "Other..." we bring up the calibrate screen dialog        var rv = { newdpi : 0 };        calscreen = window.openDialog("chrome://communicator/content/pref/pref-calibrate-screen.xul",                                       "_blank",                                       "modal,chrome,centerscreen,resizable=no,titlebar",                                      rv);        if (rv.newdpi != -1)           {            // They have entered values, and we have a DPI value back            var dpi = screenResolution.getAttribute( "dpi" );            setResolution ( rv.newdpi );          }        else          {            // They've cancelled. We can't leave "Other..." selected, so...            var defaultResolution = document.getElementById("defaultResolution");            screenResolution.selectedItem = defaultResolution;            userResolution.setAttribute("hidden", "true");          }      }    else if (!(screenResolution.value == userResolution.value))      {        // User has selected one of the hard-coded resolutions        userResolution.setAttribute("hidden", "true");      }  }
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/ed63cc7b74951af7da424791bbd50758eb1d4272/pref-fonts.js/clean/xpfe/components/prefwindow/resources/content/pref-fonts.js