Bug #327641 --> add back the open menu item to the folder pane context menu.

mail/base/content/mailWindowOverlay.xul

@@ -696,7 +696,12 @@
 
   <popup id="folderPaneContext" onpopupshowing="return fillFolderPaneContextMenu();"
     onpopuphiding="if (event.target == this) folderPaneOnPopupHiding();">
-    
+
+    <menuitem id="folderPaneContext-openNewWindow" 
+              label="&folderContextOpenNewWindow.label;"
+              accesskey="&folderContextOpenNewWindow.accesskey;"
+              oncommand="MsgOpenNewWindowForFolder(null,-1);"/>              
+              
     <menuitem id="folderPaneContext-searchMessages"
         label="&folderContextSearchMessages.label;"
         accesskey="&folderContextSearchMessages.accesskey;"

mail/locales/en-US/chrome/messenger/messenger.dtd

@@ -471,6 +471,8 @@
 <!ENTITY folderSizeColumn.label "Size">
 
 <!-- Folder Pane Context Menu -->
+<!ENTITY folderContextOpenNewWindow.label "Open">
+<!ENTITY folderContextOpenNewWindow.accesskey "O">
 <!ENTITY folderContextRename.label "Rename">
 <!ENTITY folderContextRename.accesskey "R">
 <!ENTITY folderContextRemove.label "Delete">