Bug 1774177 - Fix open message in containing folder for standalone message windows. r=freaktechnik

Fix opening, and also prevent showing the menu item if it's a message opened from the file system.

Differential Revision: https://phabricator.services.mozilla.com/D149237

--HG--
extra : rebase_source : 8d8225c8d8d8be023e44a58495d5262d8cc6a7a8
extra : amend_source : f1f9ed4e6bff7584f4e295f64d0a7aec1902d3c2

mail/base/content/mailWindowOverlay.js

@@ -2211,6 +2211,10 @@ function MsgMoveMessage(aDestFolder) {
   Services.prefs.setBoolPref("mail.last_msg_movecopy_was_move", true);
 }
 
+function OpenContainingFolder() {
+  MailUtils.displayMessageInFolderTab(gMessageDisplay.displayedMessage);
+}
+
 /**
  * Calls the ComposeMessage function with the desired type, and proper default
  * based on the event that fired it.

mail/base/content/msgMail3PaneWindow.js

@@ -1864,14 +1864,6 @@ function OpenMessageInNewTab(msgHdr, tabParams = {}) {
   }
 }
 
-function OpenContainingFolder() {
-  if (!gFolderDisplay.selectedMessage) {
-    return;
-  }
-
-  MailUtils.displayMessageInFolderTab(gFolderDisplay.selectedMessage);
-}
-
 function ThreadTreeOnClick(event) {
   var threadTree = document.getElementById("threadTree");
 

mail/base/content/nsContextMenu.js

@@ -596,7 +596,9 @@ class nsContextMenu {
     );
     this.showItem(
       "mailContext-openContainingFolder",
-      !gFolderDisplay.folderPaneVisible && this.numSelectedMessages == 1
+      !gFolderDisplay.folderPaneVisible &&
+        this.numSelectedMessages == 1 &&
+        !gMessageDisplay.isDummy
     );
 
     this.setSingleSelection("mailContext-replySender");