Bug 1708909 - Error pop up not appearing when email address is invalid. r=frg

suite/locales/en-US/chrome/mailnews/compose/composeMsgs.properties

@@ -137,18 +137,21 @@ chooseFileToAttach=Attach File(s)
 ##
 windowTitlePrefix=Compose:
 
-## String used by the empty subject dialog
+## Strings used by the empty subject dialog.
 subjectEmptyTitle=Subject Reminder
 subjectEmptyMessage=Your message doesn't have a subject.
 sendWithEmptySubjectButton=&Send Without Subject
 cancelSendingButton=&Cancel Sending
 
-## String used by the dialog that informs the user about the newsgroup recipient
+## Strings used by the dialog that informs about lack of newsgroup support.
+noNewsgroupSupportTitle=Newsgroups Not Supported
 recipientDlogMessage=This account only supports email recipients. Continuing will ignore newsgroups.
 
-## String used by the alert that tells the user an e-mail address is invalid
+## Strings used by the alert that tells the user an e-mail address is invalid.
+addressInvalidTitle=Invalid Recipient Address
 ## LOCALIZATION NOTE (addressInvalid): %1$S is the email address
 addressInvalid=%1$S is not a valid e-mail address because it is not of the form user@host. You must correct it before sending the e-mail.
+
 genericFailureExplanation=Please verify that your Mail & Newsgroups account settings are correct and try again.
 
 ## LOCALIZATION NOTE (undisclosedRecipients): this string must use only US_ASCII characters

suite/mailnews/components/compose/content/MsgComposeCommands.js

@@ -1789,7 +1789,7 @@ function GenericSendMessage(msgType) {
         var checkbox = {value:false};
         var okToProceed = Services.prompt.confirmCheck(
                               window,
-                              sComposeMsgsBundle.getString("sendMsgTitle"),
+                              sComposeMsgsBundle.getString("noNewsgroupSupportTitle"),
                               sComposeMsgsBundle.getString("recipientDlogMessage"),
                               sComposeMsgsBundle.getString("CheckMsg"),
                               checkbox);
@@ -1939,7 +1939,7 @@ function CheckValidEmailAddress(aTo, aCC, aBCC)
     invalidStr = aBCC;
   if (invalidStr)
   {
-    var errorTitle = sComposeMsgsBundle.getString("sendMsgTitle");
+    var errorTitle = sComposeMsgsBundle.getString("addressInvalidTitle");
     var errorMsg = sComposeMsgsBundle.getFormattedString("addressInvalid", [invalidStr], 1);
     Services.prompt.alert(window, errorTitle, errorMsg);
     return false;