add: else if (event.originalTarget.localName == "listitem" && event.detail == 2) OpenSelectedAttachment(); 
context: function AttachmentBucketClicked(event){  event.currentTarget.focus();  if (event.button != 0)    return;  if (event.originalTarget.localName == "listboxbody")    goDoCommand('cmd_attachFile');}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/22fcf47f86d88832af9a7cc1dfd001e9f5e0753f/MsgComposeCommands.js/buggy/mail/components/compose/content/MsgComposeCommands.js