add:   if (treeitem) { var uri = treeitem.getAttribute("id"); try { var folder = GetMsgFolderFromUri(uri); if (folder.isServer) {  return; } } catch (ex) {  } }  
context: function FolderPaneDoubleClick(treeitem){	MsgOpenNewWindowForFolder(treeitem);}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/16939f7f712730d62261ef42cad1e5f19e3cea65/msgMail3PaneWindow.js/clean/mailnews/base/resources/content/msgMail3PaneWindow.js