tweak: scroll to top when switching pages

Author: aamiaa

src/Forms/MessageListWPF.xaml.cs

@@ -30,6 +30,8 @@ public void DisplayMessages(List<DMessage> messages, int startIdx, int endIdx)
             {
                 Messages.Add(messages[i]);
             }
+
+            mainList.ScrollIntoView(messages[startIdx]);
         }
     }
 }