rem: var fileExtension = mimeInfo.FirstExtension(); 
add: var fileExtension = mimeInfo.primaryExtension; 
context: function GetExtensionBasedOnMimeType(aMIMEType){  try {    var mimeService = null;    mimeService = Components.classes["@mozilla.org/mime;1"].getService();    mimeService = mimeService.QueryInterface(Components.interfaces.nsIMIMEService);    if (!mimeService) return "";    var mimeInfo = mimeService.GetFromMIMEType(aMIMEType);    if (!mimeInfo) return "";    var fileExtension = mimeInfo.FirstExtension();    // the MIME service likes to give back ".htm" for text/html files,    // so do a special-case fix here.    if (fileExtension == "htm")      fileExtension = "html";    return fileExtension;  }  catch (e) {}  return "";}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/5a1b42ffbb85ee722874924d0f85d8e31a8e16f7/ComposerCommands.js/buggy/editor/ui/composer/content/ComposerCommands.js