rem: EnableMenuItem("folderPaneContext-compact", folder.isCommandEnabled("cmd_compactFolder")); 
add: ShowMenuItem("folderPaneContext-compact", (numSelected <=1) && canCompact && (!folder.flags & MSG_FOLDER_FLAG_VIRTUAL)); EnableMenuItem("folderPaneContext-compact", folder.isCommandEnabled("cmd_compactFolder") && (!folder.flags & MSG_FOLDER_FLAG_VIRTUAL)); 
context: function SetupCompactMenuItem(folderResource, numSelected){  var folderTree = GetFolderTree();  var canCompact = GetFolderAttribute(folderTree, folderResource, "CanCompact") == "true";  ShowMenuItem("folderPaneContext-compact", (numSelected <=1) && canCompact);  var folder = GetMsgFolderFromResource(folderResource);  EnableMenuItem("folderPaneContext-compact", folder.isCommandEnabled("cmd_compactFolder"));  if(canCompact)  {    SetMenuItemLabel("folderPaneContext-compact", gMessengerBundle.getString("compactFolder"));  }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/164d93ffb2b3b948d9931192518b30be54b959d1/mailContextMenus.js/clean/mail/base/content/mailContextMenus.js