Fix for bug 36480. Add function to switch the signature. R=putterman

git-svn-id: svn://10.0.0.236/trunk@75767 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/mailnews/compose/resources/content/MsgComposeCommands.js

@@ -1528,6 +1528,10 @@ function LoadIdentity(startup)
           
           if (needToCleanUp)
             awCleanupRows();
+
+          try {
+            msgCompose.SetSignature(currentIdentity);
+          } catch (ex) { dump("### Cannot set the signature: " + ex + "\n");}
         }
         
         //Setup autocomplete session, we can doit from here as it's use as a service